Enable browse-url to buttonize buffers

This patch also moves the internal/external browser logic from
shr to browse-url, where it belongs more naturally.

* doc/misc/eww.texi (Basics): Adjust to browse-url-external-browser.

* doc/misc/gnus.texi (Article Commands): Ditto.

* lisp/gnus/gnus-art.el (gnus-button-url-regexp): Default to
`browse-url-button-regexp', which has taken over the definition
previously enjoyed by this variable.

* lisp/gnus/gnus-sum.el (gnus-summary-browse-url): Adjust usage.

* lisp/net/browse-url.el (browse-url--browser-defcustom-type): New
internal variable...
(browse-url-browser-function, browse-url-external-browser): Used
by these two; the latter of which is a new variable.
(browse-url-botton-regexp): New variable.
(browse-url-button-map): New keymap.
(browse-url-button): New face.
(browse-url-add-buttons): New function to add clickable browse-url
buttons to almost any buffer.
(browse-url-button-open): New command.
(browse-url-button-copy): New command.

* lisp/net/eww.el (eww-browse-with-external-browser)
(eww-follow-link): Adjust usage.

* lisp/net/shr.el (shr-external-browser): Make an obsolete alias
of `browse-url-external-browser'.
(shr-browse-url): Adjust usage.

8 files changed, 201 insertions, 201 deletions

diff --git a/doc/misc/eww.texi b/doc/misc/eww.texi
index 8dc58e84257..cd74aa32c77 100644
--- a/doc/misc/eww.texi
+++ b/doc/misc/eww.texi
@@ -187,7 +187,7 @@ switch EWW buffers through a minibuffer prompt, press @kbd{s}
 (@code{eww-switch-to-buffer}).
 
 @findex eww-browse-with-external-browser
-@vindex shr-external-browser
+@vindex browse-url-external-browser
 @vindex eww-use-external-browser-for-content-type
 @kindex &
 @cindex External Browser
@@ -197,7 +197,7 @@ or are not implemented (E.g., JavaScript).  If you have trouble
 viewing a website with EWW then hit @kbd{&}
 (@code{eww-browse-with-external-browser}) inside the EWW buffer to
 open the website in the external browser specified by
-@code{shr-external-browser}.  Some content types, such as video or
+@code{browse-url-external-browser}.  Some content types, such as video or
 audio content, do not make sense to display in GNU Emacs at all.  You
 can tell EWW to open specific content automatically in an external
 browser by customizing
diff --git a/doc/misc/gnus.texi b/doc/misc/gnus.texi
index 3968fa58377..7a3322d9fc0 100644
--- a/doc/misc/gnus.texi
+++ b/doc/misc/gnus.texi
@@ -10164,7 +10164,7 @@ do so.
 @findex gnus-summary-browse-url
 Scan the article buffer for links, and offer them to the user for
 browsing with @code{browse-url}.  With a prefix argument, browse with
-@code{shr-external-browser} instead.
+@code{browse-url-external-browser} instead.
 
 @end table
 
diff --git a/etc/NEWS b/etc/NEWS
index cccb8017bd4..6517f1938c2 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -765,6 +765,12 @@ start of a sentence or at '(point-min)', else '@ref'.
 It now treats the optional 2nd argument to mean that the URL should be
 shown in the currently selected window.
 
+*** A new function, 'browse-url-add-buttons' can be used to add clickable
+links to most ordinary special-mode buffers that display text that
+have URLs embedded.  'browse-url-button-regexp' controls what's
+considered a button.
+
+*** A new variable, 'browse-url-external-browser', has been added.
 ** Comint
 
 +++
@@ -1037,6 +1043,10 @@ has been executed.
 If set, shr will not render tags with attribute 'aria-hidden="true"'.
 This attribute is meant to tell screen readers to ignore a tag.
 
++++
+*** 'shr-external-browser' has been made into an obsolete alias
+of 'browse-url-external-browser'.
+
 ---
 *** 'shr-tag-ol' now respects the ordered list 'start' attribute.
 
diff --git a/lisp/gnus/gnus-art.el b/lisp/gnus/gnus-art.el
index 65e1c8106d5..89f57712c56 100644
--- a/lisp/gnus/gnus-art.el
+++ b/lisp/gnus/gnus-art.el
@@ -7343,27 +7343,9 @@ groups."
 
 ;; Written by Per Abrahamsen <abraham@iesd.auc.dk>.
 
-;;; Internal Variables:
-
-(defcustom gnus-button-url-regexp
-  (concat
-   "\\b\\(\\(www\\.\\|\\(s?https?\\|ftp\\|file\\|gopher\\|"
-   "nntp\\|news\\|telnet\\|wais\\|mailto\\|info\\):\\)"
-   "\\(//[-a-z0-9_.]+:[0-9]*\\)?"
-   (let ((chars "-a-z0-9_=#$@~%&*+\\/[:word:]")
-         (punct "!?:;.,"))
-     (concat
-      "\\(?:"
-      ;; Match paired parentheses, e.g. in Wikipedia URLs:
-      ;; http://thread.gmane.org/47B4E3B2.3050402@gmail.com
-      "[" chars punct "]+" "(" "[" chars punct "]+" "[" chars "]*)"
-      "\\(?:" "[" chars punct "]+" "[" chars "]" "\\)?"
-      "\\|"
-      "[" chars punct "]+" "[" chars "]"
-      "\\)"))
-   "\\)")
+(defcustom gnus-button-url-regexp browse-url-button-regexp
   "Regular expression that matches URLs."
-  :version "24.4"
+  :version "27.1"
   :group 'gnus-article-buttons
   :type 'regexp)
 
diff --git a/lisp/gnus/gnus-sum.el b/lisp/gnus/gnus-sum.el
index b239890c884..d3103bd4b20 100644
--- a/lisp/gnus/gnus-sum.el
+++ b/lisp/gnus/gnus-sum.el
@@ -9478,7 +9478,7 @@ The 1st element is the widget named by `gnus-collect-urls-primary-text'."
   "Scan the current article body for links, and offer to browse them.
 
 Links are opened using `browse-url' unless a prefix argument is
-given: Then `shr-external-browser' is used instead.
+given: Then `browse-url-external-browser' is used instead.
 
 If only one link is found, browse that directly, otherwise use
 completion to select a link.  The first link marked in the
@@ -9502,7 +9502,7 @@ default."
                                     (car urls)))))
       (if target
           (if external
-              (funcall shr-external-browser target)
+              (funcall browse-url-external-browser target)
             (browse-url target))
         (message "No URLs found.")))))
 
diff --git a/lisp/net/browse-url.el b/lisp/net/browse-url.el
index aa31e25fa91..17b6d36ca87 100644
--- a/lisp/net/browse-url.el
+++ b/lisp/net/browse-url.el
@@ -131,9 +131,36 @@
   :group 'external
   :group 'comm)
 
+(defvar browse-url--browser-defcustom-type
+  '(choice
+    (function-item :tag "Emacs W3" :value  browse-url-w3)
+    (function-item :tag "eww" :value  eww-browse-url)
+    (function-item :tag "Mozilla" :value  browse-url-mozilla)
+    (function-item :tag "Firefox" :value browse-url-firefox)
+    (function-item :tag "Google Chrome" :value browse-url-chrome)
+    (function-item :tag "Chromium" :value browse-url-chromium)
+    (function-item :tag "Epiphany" :value  browse-url-epiphany)
+    (function-item :tag "Conkeror" :value  browse-url-conkeror)
+    (function-item :tag "Text browser in an xterm window"
+                   :value browse-url-text-xterm)
+    (function-item :tag "Text browser in an Emacs window"
+                   :value browse-url-text-emacs)
+    (function-item :tag "KDE" :value browse-url-kde)
+    (function-item :tag "Elinks" :value browse-url-elinks)
+    (function-item :tag "Specified by `Browse Url Generic Program'"
+                   :value browse-url-generic)
+    (function-item :tag "Default Windows browser"
+                   :value browse-url-default-windows-browser)
+    (function-item :tag "Default macOS browser"
+                   :value browse-url-default-macosx-browser)
+    (function-item :tag "Default browser"
+                   :value browse-url-default-browser)
+    (function :tag "Your own function")
+    (alist :tag "Regexp/function association list"
+           :key-type regexp :value-type function)))
+
 ;;;###autoload
-(defcustom browse-url-browser-function
-  'browse-url-default-browser
+(defcustom browse-url-browser-function 'browse-url-default-browser
   "Function to display the current buffer in a WWW browser.
 This is used by the `browse-url-at-point', `browse-url-at-mouse', and
 `browse-url-of-file' commands.
@@ -143,34 +170,17 @@ If the value is not a function it should be a list of pairs
 associated with the first REGEXP which matches the current URL.  The
 function is passed the URL and any other args of `browse-url'.  The last
 regexp should probably be \".\" to specify a default browser."
-  :type '(choice
-          (function-item :tag "Emacs W3" :value  browse-url-w3)
-          (function-item :tag "eww" :value  eww-browse-url)
-          (function-item :tag "Mozilla" :value  browse-url-mozilla)
-          (function-item :tag "Firefox" :value browse-url-firefox)
-          (function-item :tag "Google Chrome" :value browse-url-chrome)
-          (function-item :tag "Chromium" :value browse-url-chromium)
-          (function-item :tag "Epiphany" :value  browse-url-epiphany)
-          (function-item :tag "Conkeror" :value  browse-url-conkeror)
-          (function-item :tag "Text browser in an xterm window"
-                         :value browse-url-text-xterm)
-          (function-item :tag "Text browser in an Emacs window"
-                         :value browse-url-text-emacs)
-          (function-item :tag "KDE" :value browse-url-kde)
-          (function-item :tag "Elinks" :value browse-url-elinks)
-          (function-item :tag "Specified by `Browse Url Generic Program'"
-                         :value browse-url-generic)
-          (function-item :tag "Default Windows browser"
-                         :value browse-url-default-windows-browser)
-          (function-item :tag "Default macOS browser"
-                         :value browse-url-default-macosx-browser)
-          (function-item :tag "Default browser"
-                         :value browse-url-default-browser)
-          (function :tag "Your own function")
-          (alist :tag "Regexp/function association list"
-                 :key-type regexp :value-type function))
-  :version "24.1"
-  :group 'browse-url)
+  :type browse-url--browser-defcustom-type
+  :version "24.1")
+
+(defcustom browse-url-external-browser 'browse-url-default-browser
+  "Function used to launch an external browser.
+This can actually be any browser, internal or external, used as
+the secondary browser choice, and is typically used when giving a
+prefix argument to the URL-opening command (in those modes that
+support this (for instance, eww/shr)."
+  :version "27.1"
+  :type browse-url--browser-defcustom-type)
 
 (defcustom browse-url-mailto-function 'browse-url-mail
   "Function to display mailto: links.
@@ -181,8 +191,7 @@ be used instead."
   :type '(choice
           (function-item :tag "Emacs Mail" :value browse-url-mail)
           (function-item :tag "None" nil))
-  :version "24.1"
-  :group 'browse-url)
+  :version "24.1")
 
 (defcustom browse-url-man-function 'browse-url-man
   "Function to display man: links."
@@ -190,8 +199,28 @@ be used instead."
           (function-item :tag "Emacs Man" :value browse-url-man)
           (const :tag "None" nil)
           (function :tag "Other function"))
-  :version "26.1"
-  :group 'browse-url)
+  :version "26.1")
+
+(defcustom browse-url-button-regexp
+  (concat
+   "\\b\\(\\(www\\.\\|\\(s?https?\\|ftp\\|file\\|gopher\\|"
+   "nntp\\|news\\|telnet\\|wais\\|mailto\\|info\\):\\)"
+   "\\(//[-a-z0-9_.]+:[0-9]*\\)?"
+   (let ((chars "-a-z0-9_=#$@~%&*+\\/[:word:]")
+         (punct "!?:;.,"))
+     (concat
+      "\\(?:"
+      ;; Match paired parentheses, e.g. in Wikipedia URLs:
+      ;; http://thread.gmane.org/47B4E3B2.3050402@gmail.com
+      "[" chars punct "]+" "(" "[" chars punct "]+" "[" chars "]*)"
+      "\\(?:" "[" chars punct "]+" "[" chars "]" "\\)?"
+      "\\|"
+      "[" chars punct "]+" "[" chars "]"
+      "\\)"))
+   "\\)")
+  "Regular expression that matches URLs."
+  :version "27.1"
+  :type 'regexp)
 
 (defcustom browse-url-netscape-program "netscape"
   ;; Info about netscape-remote from Karl Berry.
@@ -202,15 +231,13 @@ The free program `netscape-remote' from
 up very much quicker than `netscape'.  Reported to compile on a GNU
 system, given vroot.h from the same directory, with cc flags
  -DSTANDALONE -L/usr/X11R6/lib -lXmu -lX11."
-  :type 'string
-  :group 'browse-url)
+  :type 'string)
 
 (make-obsolete-variable 'browse-url-netscape-program nil "25.1")
 
 (defcustom browse-url-netscape-arguments nil
   "A list of strings to pass to Netscape as arguments."
-  :type '(repeat (string :tag "Argument"))
-  :group 'browse-url)
+  :type '(repeat (string :tag "Argument")))
 
 (make-obsolete-variable 'browse-url-netscape-arguments nil "25.1")
 
@@ -218,33 +245,27 @@ system, given vroot.h from the same directory, with cc flags
   "A list of strings to pass to Netscape when it starts up.
 Defaults to the value of `browse-url-netscape-arguments' at the time
 `browse-url' is loaded."
-  :type '(repeat (string :tag "Argument"))
-
-  :group 'browse-url)
+  :type '(repeat (string :tag "Argument")))
 
 (make-obsolete-variable 'browse-url-netscape-startup-arguments nil "25.1")
 
 (defcustom browse-url-browser-display nil
   "The X display for running the browser, if not same as Emacs's."
-  :type '(choice string (const :tag "Default" nil))
-  :group 'browse-url)
+  :type '(choice string (const :tag "Default" nil)))
 
 (defcustom browse-url-mozilla-program "mozilla"
   "The name by which to invoke Mozilla."
-  :type 'string
-  :group 'browse-url)
+  :type 'string)
 
 (defcustom browse-url-mozilla-arguments nil
   "A list of strings to pass to Mozilla as arguments."
-  :type '(repeat (string :tag "Argument"))
-  :group 'browse-url)
+  :type '(repeat (string :tag "Argument")))
 
 (defcustom browse-url-mozilla-startup-arguments browse-url-mozilla-arguments
   "A list of strings to pass to Mozilla when it starts up.
 Defaults to the value of `browse-url-mozilla-arguments' at the time
 `browse-url' is loaded."
-  :type '(repeat (string :tag "Argument"))
-  :group 'browse-url)
+  :type '(repeat (string :tag "Argument")))
 
 (defcustom browse-url-firefox-program
   (let ((candidates '("icecat" "iceweasel" "firefox")))
@@ -252,20 +273,17 @@ Defaults to the value of `browse-url-mozilla-arguments' at the time
       (setq candidates (cdr candidates)))
     (or (car candidates) "firefox"))
   "The name by which to invoke Firefox or a variant of it."
-  :type 'string
-  :group 'browse-url)
+  :type 'string)
 
 (defcustom browse-url-firefox-arguments nil
   "A list of strings to pass to Firefox (or variant) as arguments."
-  :type '(repeat (string :tag "Argument"))
-  :group 'browse-url)
+  :type '(repeat (string :tag "Argument")))
 
 (defcustom browse-url-firefox-startup-arguments browse-url-firefox-arguments
   "A list of strings to pass to Firefox (or variant) when it starts up.
 Defaults to the value of `browse-url-firefox-arguments' at the time
 `browse-url' is loaded."
-  :type '(repeat (string :tag "Argument"))
-  :group 'browse-url)
+  :type '(repeat (string :tag "Argument")))
 
 (make-obsolete-variable 'browse-url-firefox-startup-arguments
                         "it no longer has any effect." "24.5")
@@ -277,14 +295,12 @@ Defaults to the value of `browse-url-firefox-arguments' at the time
     (or (car candidates) "chromium"))
   "The name by which to invoke the Chrome browser."
   :type 'string
-  :version "25.1"
-  :group 'browse-url)
+  :version "25.1")
 
 (defcustom browse-url-chrome-arguments nil
   "A list of strings to pass to Google Chrome as arguments."
   :type '(repeat (string :tag "Argument"))
-  :version "25.1"
-  :group 'browse-url)
+  :version "25.1")
 
 (defcustom browse-url-chromium-program
   (let ((candidates '("chromium" "chromium-browser")))
@@ -293,26 +309,22 @@ Defaults to the value of `browse-url-firefox-arguments' at the time
     (or (car candidates) "chromium"))
   "The name by which to invoke Chromium."
   :type 'string
-  :version "24.1"
-  :group 'browse-url)
+  :version "24.1")
 
 (defcustom browse-url-chromium-arguments nil
   "A list of strings to pass to Chromium as arguments."
   :type '(repeat (string :tag "Argument"))
-  :version "24.1"
-  :group 'browse-url)
+  :version "24.1")
 
 (defcustom browse-url-galeon-program "galeon"
   "The name by which to invoke Galeon."
-  :type 'string
-  :group 'browse-url)
+  :type 'string)
 
 (make-obsolete-variable 'browse-url-galeon-program nil "25.1")
 
 (defcustom browse-url-galeon-arguments nil
   "A list of strings to pass to Galeon as arguments."
-  :type '(repeat (string :tag "Argument"))
-  :group 'browse-url)
+  :type '(repeat (string :tag "Argument")))
 
 (make-obsolete-variable 'browse-url-galeon-arguments nil "25.1")
 
@@ -320,27 +332,23 @@ Defaults to the value of `browse-url-firefox-arguments' at the time
   "A list of strings to pass to Galeon when it starts up.
 Defaults to the value of `browse-url-galeon-arguments' at the time
 `browse-url' is loaded."
-  :type '(repeat (string :tag "Argument"))
-  :group 'browse-url)
+  :type '(repeat (string :tag "Argument")))
 
 (make-obsolete-variable 'browse-url-galeon-startup-arguments nil "25.1")
 
 (defcustom browse-url-epiphany-program "epiphany"
   "The name by which to invoke Epiphany."
-  :type 'string
-  :group 'browse-url)
+  :type 'string)
 
 (defcustom browse-url-epiphany-arguments nil
   "A list of strings to pass to Epiphany as arguments."
-  :type '(repeat (string :tag "Argument"))
-  :group 'browse-url)
+  :type '(repeat (string :tag "Argument")))
 
 (defcustom browse-url-epiphany-startup-arguments browse-url-epiphany-arguments
   "A list of strings to pass to Epiphany when it starts up.
 Defaults to the value of `browse-url-epiphany-arguments' at the time
 `browse-url' is loaded."
-  :type '(repeat (string :tag "Argument"))
-  :group 'browse-url)
+  :type '(repeat (string :tag "Argument")))
 
 ;; GNOME means of invoking either Mozilla or Netscape.
 (defvar browse-url-gnome-moz-program "gnome-moz-remote")
@@ -350,8 +358,7 @@ Defaults to the value of `browse-url-epiphany-arguments' at the time
 (defcustom browse-url-gnome-moz-arguments '()
   "A list of strings passed to the GNOME mozilla viewer as arguments."
   :version "21.1"
-  :type '(repeat (string :tag "Argument"))
-  :group 'browse-url)
+  :type '(repeat (string :tag "Argument")))
 
 (make-obsolete-variable 'browse-url-gnome-moz-arguments nil "25.1")
 
@@ -359,30 +366,26 @@ Defaults to the value of `browse-url-epiphany-arguments' at the time
   "Whether to open up new windows in a tab or a new window.
 If non-nil, then open the URL in a new tab rather than a new window if
 `browse-url-mozilla' is asked to open it in a new window."
-  :type 'boolean
-  :group 'browse-url)
+  :type 'boolean)
 
 (defcustom browse-url-firefox-new-window-is-tab nil
   "Whether to open up new windows in a tab or a new window.
 If non-nil, then open the URL in a new tab rather than a new window if
 `browse-url-firefox' is asked to open it in a new window."
-  :type 'boolean
-  :group 'browse-url)
+  :type 'boolean)
 
 (defcustom browse-url-conkeror-new-window-is-buffer nil
   "Whether to open up new windows in a buffer or a new window.
 If non-nil, then open the URL in a new buffer rather than a new window if
 `browse-url-conkeror' is asked to open it in a new window."
   :version "25.1"
-  :type 'boolean
-  :group 'browse-url)
+  :type 'boolean)
 
 (defcustom browse-url-galeon-new-window-is-tab nil
   "Whether to open up new windows in a tab or a new window.
 If non-nil, then open the URL in a new tab rather than a new window if
 `browse-url-galeon' is asked to open it in a new window."
-  :type 'boolean
-  :group 'browse-url)
+  :type 'boolean)
 
 (make-obsolete-variable 'browse-url-galeon-new-window-is-tab nil "25.1")
 
@@ -390,16 +393,14 @@ If non-nil, then open the URL in a new tab rather than a new window if
   "Whether to open up new windows in a tab or a new window.
 If non-nil, then open the URL in a new tab rather than a new window if
 `browse-url-epiphany' is asked to open it in a new window."
-  :type 'boolean
-  :group 'browse-url)
+  :type 'boolean)
 
 (defcustom browse-url-netscape-new-window-is-tab nil
   "Whether to open up new windows in a tab or a new window.
 If non-nil, then open the URL in a new tab rather than a new
 window if `browse-url-netscape' is asked to open it in a new
 window."
-  :type 'boolean
-  :group 'browse-url)
+  :type 'boolean)
 
 (make-obsolete-variable 'browse-url-netscape-new-window-is-tab nil "25.1")
 
@@ -407,42 +408,36 @@ window."
   "Non-nil means always open a new browser window with appropriate browsers.
 Passing an interactive argument to \\[browse-url], or specific browser
 commands reverses the effect of this variable."
-  :type 'boolean
-  :group 'browse-url)
+  :type 'boolean)
 
 (defcustom browse-url-mosaic-program "xmosaic"
   "The name by which to invoke Mosaic (or mMosaic)."
   :type 'string
-  :version "20.3"
-  :group 'browse-url)
+  :version "20.3")
 
 (make-obsolete-variable 'browse-url-mosaic-program nil "25.1")
 
 (defcustom browse-url-mosaic-arguments nil
   "A list of strings to pass to Mosaic as arguments."
-  :type '(repeat (string :tag "Argument"))
-  :group 'browse-url)
+  :type '(repeat (string :tag "Argument")))
 
 (make-obsolete-variable 'browse-url-mosaic-arguments nil "25.1")
 
 (defcustom browse-url-mosaic-pidfile "~/.mosaicpid"
   "The name of the pidfile created by Mosaic."
-  :type 'string
-  :group 'browse-url)
+  :type 'string)
 
 (make-obsolete-variable 'browse-url-mosaic-pidfile nil "25.1")
 
 (defcustom browse-url-conkeror-program "conkeror"
   "The name by which to invoke Conkeror."
   :type 'string
-  :version "25.1"
-  :group 'browse-url)
+  :version "25.1")
 
 (defcustom browse-url-conkeror-arguments nil
   "A list of strings to pass to Conkeror as arguments."
   :version "25.1"
-  :type '(repeat (string :tag "Argument"))
-  :group 'browse-url)
+  :type '(repeat (string :tag "Argument")))
 
 (defcustom browse-url-filename-alist
   `(("^/\\(ftp@\\|anonymous@\\)?\\([^:/]+\\):/*" . "ftp://\\2/")
@@ -473,26 +468,22 @@ address to an HTTP URL:
   :type '(repeat (cons :format "%v"
                        (regexp :tag "Regexp")
                        (string :tag "Replacement")))
-  :version "25.1"
-  :group 'browse-url)
+  :version "25.1")
 
 (defcustom browse-url-save-file nil
   "If non-nil, save the buffer before displaying its file.
 Used by the `browse-url-of-file' command."
-  :type 'boolean
-  :group 'browse-url)
+  :type 'boolean)
 
 (defcustom browse-url-of-file-hook nil
   "Hook run after `browse-url-of-file' has asked a browser to load a file."
-  :type 'hook
-  :group 'browse-url)
+  :type 'hook)
 
 (defcustom browse-url-CCI-port 3003
   "Port to access XMosaic via CCI.
 This can be any number between 1024 and 65535 but must correspond to
 the value set in the browser."
-  :type 'integer
-  :group 'browse-url)
+  :type 'integer)
 
 (make-obsolete-variable 'browse-url-CCI-port nil "25.1")
 
@@ -500,8 +491,7 @@ the value set in the browser."
   "Host to access XMosaic via CCI.
 This should be the host name of the machine running XMosaic with CCI
 enabled.  The port number should be set in `browse-url-CCI-port'."
-  :type 'string
-  :group 'browse-url)
+  :type 'string)
 
 (make-obsolete-variable 'browse-url-CCI-host nil "25.1")
 
@@ -511,57 +501,48 @@ enabled.  The port number should be set in `browse-url-CCI-port'."
 (defcustom browse-url-xterm-program "xterm"
   "The name of the terminal emulator used by `browse-url-text-xterm'.
 This might, for instance, be a separate color version of xterm."
-  :type 'string
-  :group 'browse-url)
+  :type 'string)
 
 (defcustom browse-url-xterm-args nil
   "A list of strings defining options for `browse-url-xterm-program'.
 These might set its size, for instance."
-  :type '(repeat (string :tag "Argument"))
-  :group 'browse-url)
+  :type '(repeat (string :tag "Argument")))
 
 (defcustom browse-url-gnudoit-program "gnudoit"
   "The name of the `gnudoit' program used by `browse-url-w3-gnudoit'."
-  :type 'string
-  :group 'browse-url)
+  :type 'string)
 
 (defcustom browse-url-gnudoit-args '("-q")
   "A list of strings defining options for `browse-url-gnudoit-program'.
 These might set the port, for instance."
-  :type '(repeat (string :tag "Argument"))
-  :group 'browse-url)
+  :type '(repeat (string :tag "Argument")))
 
 (defcustom browse-url-generic-program nil
   "The name of the browser program used by `browse-url-generic'."
-  :type '(choice string (const :tag "None" nil))
-  :group 'browse-url)
+  :type '(choice string (const :tag "None" nil)))
 
 (defcustom browse-url-generic-args nil
   "A list of strings defining options for `browse-url-generic-program'."
-  :type '(repeat (string :tag "Argument"))
-  :group 'browse-url)
+  :type '(repeat (string :tag "Argument")))
 
 (defcustom browse-url-temp-dir temporary-file-directory
   "The name of a directory for browse-url's temporary files.
 Such files are generated by functions like `browse-url-of-region'.
 You might want to set this to somewhere with restricted read permissions
 for privacy's sake."
-  :type 'string
-  :group 'browse-url)
+  :type 'string)
 
 (defcustom browse-url-netscape-version 3
   "The version of Netscape you are using.
 This affects how URL reloading is done; the mechanism changed
 incompatibly at version 4."
-  :type 'number
-  :group 'browse-url)
+  :type 'number)
 
 (make-obsolete-variable 'browse-url-netscape-version nil "25.1")
 
 (defcustom browse-url-text-browser "lynx"
   "The name of the text browser to invoke."
   :type 'string
-  :group 'browse-url
   :version "23.1")
 
 (defcustom browse-url-text-emacs-args (and (not window-system)
@@ -572,8 +553,7 @@ The default is none in a window system, otherwise `-show_cursor' to
 indicate the position of the current link in the absence of
 highlighting, assuming the normal default for showing the cursor."
   :type '(repeat (string :tag "Argument"))
-  :version "23.1"
-  :group 'browse-url)
+  :version "23.1")
 
 (defcustom browse-url-text-input-field 'avoid
   "Action on selecting an existing text browser buffer at an input field.
@@ -586,36 +566,30 @@ down (this *won't* always work)."
   :type '(choice (const :tag "Move to try to avoid field" :value avoid)
                  (const :tag "Disregard" :value nil)
                  (const :tag "Warn, don't emit URL" :value warn))
-  :version "23.1"
-  :group 'browse-url)
+  :version "23.1")
 
 (defcustom browse-url-text-input-attempts 10
   "How many times to try to move down from a series of text browser input fields."
   :type 'integer
-  :version "23.1"
-  :group 'browse-url)
+  :version "23.1")
 
 (defcustom browse-url-text-input-delay 0.2
   "Seconds to wait for a text browser between moves down from an input field."
   :type 'number
-  :version "23.1"
-  :group 'browse-url)
+  :version "23.1")
 
 (defcustom browse-url-kde-program "kfmclient"
   "The name by which to invoke the KDE web browser."
   :type 'string
-  :version "21.1"
-  :group 'browse-url)
+  :version "21.1")
 
 (defcustom browse-url-kde-args '("openURL")
   "A list of strings defining options for `browse-url-kde-program'."
-  :type '(repeat (string :tag "Argument"))
-  :group 'browse-url)
+  :type '(repeat (string :tag "Argument")))
 
 (defcustom browse-url-elinks-wrapper '("xterm" "-e")
   "Wrapper command prepended to the Elinks command-line."
-  :type '(repeat (string :tag "Wrapper"))
-  :group 'browse-url)
+  :type '(repeat (string :tag "Wrapper")))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; URL encoding
@@ -1673,6 +1647,58 @@ from `browse-url-elinks-wrapper'."
      (error "Unrecognized exit-code %d of process `elinks'"
             exit-status))))
 
+;;; Adding buttons to a buffer to call `browse-url' when you hit them.
+
+(defvar browse-url-button-map
+  (let ((map (make-sparse-keymap)))
+    (define-key map "\r" 'browse-url-button-open)
+    (define-key map [mouse-2] 'browse-url-button-open)
+    (define-key map "w" 'browse-url-button-copy)
+    map)
+  "The keymap used for browse-url buttons.")
+
+(defface browse-url-button
+  '((t :inherit link))
+  "Face for browse-url buttons (i.e., links)."
+  :version "27.1")
+
+(defun browse-url-add-buttons ()
+  "Add clickable buttons to the text following point in the current buffer.
+Everything that matches `browse-url-button-regexp' will be made
+clickable and will use `browse-url' to open the URLs in question."
+  (let ((inhibit-read-only t))
+    (save-excursion
+      (while (re-search-forward browse-url-button-regexp nil t)
+        (add-text-properties (match-beginning 0)
+                             (match-end 0)
+                             `(help-echo "Open the URL under point"
+                                         keymap ,browse-url-button-map
+                                         face browse-url-button
+                                         button t
+                                         browse-url-data ,(match-string 0)))))))
+
+(defun browse-url-button-open (&optional external mouse-event)
+  "Follow the link under point using `browse-url'.
+If EXTERNAL (the prefix if used interactively), open with the
+external browser instead of the default one."
+  (interactive (list current-prefix-arg last-nonmenu-event))
+  (mouse-set-point mouse-event)
+  (let ((url (get-text-property (point) 'browse-url-data)))
+    (unless url
+      (error "No URL under point"))
+    (if external
+        (funcall browse-url-external-browser url)
+      (browse-url url))))
+
+(defun browse-url-button-copy ()
+  "Copy the URL under point"
+  (interactive)
+  (let ((url (get-text-property (point) 'browse-url-data)))
+    (unless url
+      (error "No URL under point"))
+    (kill-new url)
+    (message "Copied %s" url)))
+
 (provide 'browse-url)
 
 ;;; browse-url.el ends here
diff --git a/lisp/net/eww.el b/lisp/net/eww.el
index 206f9cfdf30..d839cc24c46 100644
--- a/lisp/net/eww.el
+++ b/lisp/net/eww.el
@@ -1501,13 +1501,15 @@ See URL `https://developer.mozilla.org/en-US/docs/Web/HTML/Element/Input'.")
 
 (defun eww-browse-with-external-browser (&optional url)
   "Browse the current URL with an external browser.
-The browser to used is specified by the `shr-external-browser' variable."
+The browser to used is specified by the `browse-url-external-browser' variable."
   (interactive)
-  (funcall shr-external-browser (or url (plist-get eww-data :url))))
+  (funcall browse-url-external-browser (or url (plist-get eww-data :url))))
 
 (defun eww-follow-link (&optional external mouse-event)
   "Browse the URL under point.
-If EXTERNAL is single prefix, browse the URL using `shr-external-browser'.
+If EXTERNAL is single prefix, browse the URL using
+`browse-url-external-browser'.
+
 If EXTERNAL is double prefix, browse in new buffer."
   (interactive (list current-prefix-arg last-nonmenu-event))
   (mouse-set-point mouse-event)
@@ -1518,7 +1520,7 @@ If EXTERNAL is double prefix, browse in new buffer."
      ((string-match "^mailto:" url)
       (browse-url-mail url))
      ((and (consp external) (<= (car external) 4))
-      (funcall shr-external-browser url)
+      (funcall browse-url-external-browser url)
       (shr--blink-link))
      ;; This is a #target url in the same page as the current one.
      ((and (url-target (url-generic-parse-url url))
diff --git a/lisp/net/shr.el b/lisp/net/shr.el
index 98b09ab2970..2bc25930fcb 100644
--- a/lisp/net/shr.el
+++ b/lisp/net/shr.el
@@ -53,53 +53,44 @@ width and height of the window.  If they are larger than this,
 and Emacs supports it, then the images will be rescaled down to
 fit these criteria."
   :version "24.1"
-  :group 'shr
   :type 'float)
 
 (defcustom shr-blocked-images nil
   "Images that have URLs matching this regexp will be blocked."
   :version "24.1"
-  :group 'shr
   :type '(choice (const nil) regexp))
 
 (defcustom shr-use-fonts t
   "If non-nil, use proportional fonts for text."
   :version "25.1"
-  :group 'shr
   :type 'boolean)
 
 (defcustom shr-discard-aria-hidden nil
   "If non-nil, don't render tags with `aria-hidden=\"true\"'.
 This attribute is meant to tell screen readers to ignore a tag."
   :version "27.1"
-  :group 'shr
   :type 'boolean)
 
 (defcustom shr-use-colors t
   "If non-nil, respect color specifications in the HTML."
   :version "26.1"
-  :group 'shr
   :type 'boolean)
 
 (defcustom shr-table-horizontal-line nil
   "Character used to draw horizontal table lines.
 If nil, don't draw horizontal table lines."
-  :group 'shr
   :type '(choice (const nil) character))
 
 (defcustom shr-table-vertical-line ?\s
   "Character used to draw vertical table lines."
-  :group 'shr
   :type 'character)
 
 (defcustom shr-table-corner ?\s
   "Character used to draw table corners."
-  :group 'shr
   :type 'character)
 
 (defcustom shr-hr-line ?-
   "Character used to draw hr lines."
-  :group 'shr
   :type 'character)
 
 (defcustom shr-width nil
@@ -110,8 +101,7 @@ If `shr-use-fonts' is set, the mean character width is used to
 compute the pixel width, which is used instead."
   :version "25.1"
   :type '(choice (integer :tag "Fixed width in characters")
-                 (const   :tag "Use the width of the window" nil))
-  :group 'shr)
+                 (const   :tag "Use the width of the window" nil)))
 
 (defcustom shr-bullet "* "
   "Bullet used for unordered lists.
@@ -119,19 +109,14 @@ Alternative suggestions are:
 - \"  \"
 - \"  \""
   :version "24.4"
-  :type 'string
-  :group 'shr)
+  :type 'string)
 
-(defcustom shr-external-browser 'browse-url-default-browser
-  "Function used to launch an external browser."
-  :version "24.4"
-  :group 'shr
-  :type 'function)
+(define-obsolete-variable-alias 'shr-external-browser
+  'browse-url-external-browser "27.1")
 
 (defcustom shr-image-animate t
   "Non nil means that images that can be animated will be."
   :version "24.4"
-  :group 'shr
   :type 'boolean)
 
 (defvar shr-content-function nil
@@ -144,28 +129,24 @@ cid: URL as the argument.")
 
 (defface shr-strike-through '((t :strike-through t))
   "Face for <s> elements."
-  :version "24.1"
-  :group 'shr)
+  :version "24.1")
 
 (defface shr-link
   '((t :inherit link))
   "Face for link elements."
-  :version "24.1"
-  :group 'shr)
+  :version "24.1")
 
 (defface shr-selected-link
   '((t :inherit shr-link :background "red"))
   "Temporary face for externally visited link elements.
 When a link is visited with an external browser, the link
 temporarily blinks with this face."
-  :version "27.1"
-  :group 'shr)
+  :version "27.1")
 
 (defface shr-abbreviation
   '((t :inherit underline :underline (:style wave)))
   "Face for <abbr> elements."
-  :version "27.1"
-  :group 'shr)
+  :version "27.1")
 
 (defvar shr-inhibit-images nil
   "If non-nil, inhibit loading images.")
@@ -973,7 +954,7 @@ size, and full-buffer size."
 (defun shr-browse-url (&optional external mouse-event)
   "Browse the URL at point using `browse-url'.
 If EXTERNAL is non-nil (interactively, the prefix argument), browse
-the URL using `shr-external-browser'.
+the URL using `browse-url-external-browser'.
 If this function is invoked by a mouse click, it will browse the URL
 at the position of the click.  Optional argument MOUSE-EVENT describes
 the mouse click event."
@@ -988,7 +969,7 @@ the mouse click event."
      (t
       (if external
           (progn
-            (funcall shr-external-browser url)
+            (funcall browse-url-external-browser url)
             (shr--blink-link))
         (browse-url url))))))
 
@@ -1534,7 +1515,6 @@ The key element should be a regexp matched against the type of the source or
 url if no type is specified.  The value should be a float in the range 0.0 to
 1.0.  Media elements with higher value are preferred."
   :version "24.4"
-  :group 'shr
   :type '(alist :key-type regexp :value-type float))
 
 (defun shr--get-media-pref (elem)