> [...] which I can only presume does some poor parsing of xdg-settings output (including stderr?) when determining if it is itself the default browser.
I had a look (https://searchfox.org/mozilla-central/source/browser/components/shell/nsGNOMEShellService.cpp#184-204) and it does suppress stderr, but the problem is the non-zero exit status that the error results in. Firefox will only consider itself the default browser if the command exits with 0 exit status *and* prints "yes".
> [...] which I can only presume does some poor parsing of xdg-settings output (including stderr?) when determining if it is itself the default browser.
I had a look (https:/ /searchfox. org/mozilla- central/ source/ browser/ components/ shell/nsGNOMESh ellService. cpp#184- 204) and it does suppress stderr, but the problem is the non-zero exit status that the error results in. Firefox will only consider itself the default browser if the command exits with 0 exit status *and* prints "yes".