Under Gnome, Firefox will open the wrong URL when launched by
webbrowser.  For example after running the following interactive session:

bingham@grizzly:~> python
Python 2.5.1 (r251:54863, Jun  6 2007, 13:42:30)
[GCC 4.1.2 20061115 (prerelease) (SUSE Linux)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import webbrowser
>>> webbrowser.open('http://www.python.org')
True

Firefox attempts to open the URL
file:///home/bingham/%22http://www.python.org%22.

This is caused by a bug in the Python standard library's webbrowser
module that only affects machines running Gnome.

On Gnome, webbrowser runs the command

gconftool-2 -g /desktop/gnome/url-handlers/http/command 2>/dev/null

to find the web browser, which prints out a browser command line like

/pkgs/Firefox/2.0/firefox "%s"

The quotes around "%s" are preserved when passing the command-line
arguments. The quotes prevent firefox from recognizing the URL and
firefox falls back to treating it as a file name. The webbrowser module
already handles extra quoting around the URL for the BROWSER environment
variable and this same treatment should be applied to the result of
gconftool-2.

The BROWSER environment variable issue, now fixed, is described at
http://bugs.python.org/issue1684254.  The present issue was discussed in
an Ubuntu bug report
(https://bugs.launchpad.net/ubuntu/+source/python2.5/+bug/83974) but was
not resolved.