gh-125231 register firefox channels as Mozilla controller

Doc/library/webbrowser.rst

@@ -186,6 +186,8 @@ for the controller classes, all defined in this module.
 +------------------------+-----------------------------------------+-------+
 | ``'iosbrowser'``       | ``IOSBrowser``                          | \(4)  |
 +------------------------+-----------------------------------------+-------+
+| ``'firefox-'``         | ``Mozilla('mozilla')``                  | \(5)  |
++------------------------+-----------------------------------------+-------+
 
 Notes:
 
@@ -205,6 +207,10 @@ Notes:
 (4)
    Only on iOS.
 
+(5)
+   firefox- are Firefox channels, such as firefox-dev, firefox-aurora,
+   firefox-beta, firefox-nightly, etc.
+
 .. versionadded:: 3.2
    A new :class:`!MacOSXOSAScript` class has been added
    and is used on Mac instead of the previous :class:`!MacOSX` class.

Lib/webbrowser.py

@@ -7,6 +7,7 @@
 import sys
 import subprocess
 import threading
+import glob
 
 __all__ = ["Error", "open", "open_new", "open_new_tab", "get", "register"]
 
@@ -486,6 +487,16 @@ def register_X_browsers():
     if shutil.which("microsoft-edge"):
         register("microsoft-edge", None, Edge("microsoft-edge"))
 
+    # firefox-dev, firefox-aurora,firefox-beta, firefox-nightly, etc.
+    firefox_channels = {
+        name
+        for path_dir in os.environ["PATH"].split(os.pathsep)
+        for exe in glob.glob(os.path.join(path_dir, "firefox-*"))
+        if (name := os.path.basename(exe)) and shutil.which(name)
+    }
+
+    for browser in firefox_channels:
+        register(browser, None, Mozilla(browser))
 
 def register_standard_browsers():
     global _tryorder