Yes. Definitely both are needed.
To be totally clear, it doesn’t stop it from being set as the default browser. It stops the default browser check from working properly so it nags that it isn’t the default browser(even if it actually is) until you tell it to stop checking.
How do you set it as the default browser? The “Make Default” button in Preferences → General does not work.
Yes, but Firefox still thinks it’s not the default browser.
Right. Isn’t that what I wrote? The check to see if it is the default browser fails.
Err…I am confused here?
Oh, I see what you mean. I misunderstood you.
Anyway, the solution is to just disable the check and everything is fine.
so finally from Development perspective:
We will never maintain our own Browser in repository, we keep it simple, the only apps we do maintain are this ones needed for the ISO to work and for EndeavourOS apps and theming. DE’S are shipped vanilla, so why we should ship a non vanilla Browser?
Firefox is installed as it is without language pack or any addons.
We choose firefox as the default by reason, it is the only last man standing free non chromium based browser.
Well like I said from my POV the question is moot (and “solved” since 20 posts back). There was no interest in something like that and for me, its fixable on my end (with some complexities with the gpg key signing for that app) so unless others want to know how to fix the GPG signing issue for those specific apps - there is nothing I can add. The discussion was interesting as some alternatives and points that may not have been appearent came to light.
I can’t answer why you make your choices in what you remove or include? And beyond Firefox being a bit clunky in that DE I don’t mind the changes you’ve done to Plasma or the KDE apps you included and the ones you didn’t. They are easy to add or remove.
Personally I think you should make the choices you prefer, whatever they may be.
EndeavourOS is not like other distros where one man is deciding what to include and what not we try to simple include only what is needed as a stable base to build your system on your personal preferences.
We default to a full set of libs, apps are a min imal set, Desktops are without any configuration changed they came as there are provided on archrepository, but not cluttered with all extra packages.
But yes your question cleared already 
It is only that i do not like that users think that we do not listen, to what they would like to have included, the community is the core of EndeavourOS, but the goal of the installer is to provid ea stable framework to install a stable base system, with a minimum of workload to the developer doing this aside from their normal live and love.
