That's the beauty of free and open source code. Just because a project is discontinued by the original developers does not mean it is dead forever. Anyone can pick it back up and work with it again.
I understand that but do you think all the developers of all the addons will continue upgrading and improving their addons for a few Basilisk users? I doubt that.
If you read anywhere else on the forum - or just this thread, even - you will find that Basilisk based on Firefox 55-56, not Quantum, and that its purpose is not to replace Pale Moon at all, but to complement it in specific ways. Both browsers will continue to support XUL-based addons for the foreseeable future.
Well, Moonchild said this:
"What does this have to do with Pale Moon?
UXP will be the long-term future for Pale Moon. As such, we need something (an application) to develop this alongside our current browser platform and back-end. Eventually, Pale Moon will become a "UXP application", just like Basilisk is now. UXP applications retain full customization and freedom in application layout code, so the "look and feel" will not significantly change when Pale Moon is moved to the new platform (somewhere in 2018). "
So, Basilisk seems to be kind of a precursor to what Pale Moon will soon become.
And yes, I was obviously wrong about Basilisk being based on Quantum but I have to say it is a bit confusing since even websites think that Basilisk is Firefox Quantum, that's why I thought so too.
But if that is not the case it's probably just a user agent setting in Basilisk.