We've been using xdg-open as the first choice for the Debian packages and
subsequently the Ubuntu packages for over a year now and didn't receive such
a problem report so I suspect that it makes more sense to fix the broken
setup instead of reverting this change.
The only way you can get to the browser bit is (a) not to be using KDE,
Gnome, or XFCE, and (b) not to have a working version of mimeopen
installed. That's a perfectly sensible setup, but in that case we
shouldn't use xdg-open, I'd guess. If so, then that will complicate the
configure script. How much, I don't know. Maybe we could borrow the
detectDE bit from xdg-open, modified for Python, and then check for
mimeopen if we don't find one of the preconfigured desktops, and then,
only if all of that succeeds, use xdg-open, assuming we found it.
Richard