#5935: mention that BROWSER is looked for in PATH.

Doc/library/webbrowser.rst

@@ -22,7 +22,7 @@ override the platform default list of browsers, as a os.pathsep-separated list
 of browsers to try in order.  When the value of a list part contains the string
 ``%s``, then it is  interpreted as a literal browser command line to be used
 with the argument URL substituted for ``%s``; if the part does not contain
-``%s``, it is simply interpreted as the name of the browser to launch.
+``%s``, it is simply interpreted as the name of the browser to launch. [1]_
 
 For non-Unix platforms, or when a remote browser is available on Unix, the
 controlling process will not wait for the user to finish with the browser, but
@@ -201,3 +201,8 @@ module-level convenience functions:
 
    .. versionadded:: 2.5
 
+
+.. rubric:: Footnotes
+
+.. [1] Executables named here without a full path will be searched in the
+       directories given in the :envvar:`PATH` environment variable.