Re: eww-browse-with-external-browser unexpectedly starts up librewolf instead of firefox

> From: Eric S Fraga <[email protected]>
> Date: Mon, 01 Jun 2026 14:17:02 +0100
> 
> a recent update of Debian Linux (the only action I've done recently that
> could have changed anything, I believe) has led to
> eww-browse-with-external-browser, bound to & by default in eww, to start
> up librewolf as the graphical browser instead of firefox.  Putting aside
> any arguments about which browser might be better, I want firefox (at
> least for the moment).
> 
> I cannot find any mention of librewolf in my Emacs configuration.  eww
> invokes browse-url-secondary-browser-function which, in my
> configuration, is set to browse-url-firefox.  However, invoking
> browse-url-firefox actually starts librewolf!
> 
> Looking at the code for browse-url-firefox, it appears that the process
> command that is invoked is "firefox URL".  If I type this directly in a
> shell window (e.g. eshell) or a separate X terminal, I get firefox as
> expected.  Yet M-x browse-url-firefox RET <some url> RET starts up
> librewolf.  I am *so* confused!
> 
> Any suggestions of where to look for identifying this change in
> behaviour?  I want browse-url-firefox to use firefox!  The hint is in
> the name. ;-)

See the variable browse-url-firefox-program.  I's a user option, so if
the default value is not to your liking, just customize it.