This is actually based on the Goanna web engine (a fork of the Firefox / Gecko web engine) derived from the https://www.basilisk-browser.org/ . You can find out more here - https://forum.palemoon.org/viewtopic.php?f=69&p=275829#p2758... .

Ah, that explains why there is still NPAPI plugin support.

Yup. The only browsers that still support Flash.

The same complaint in my original comment applies - at what version was it forked from, what version of Firefox is it equivalent to?

https://www.basilisk-browser.org/features.html

Basilisk supports the technologies required for the modern web, while deliberately avoiding the rapid architectural and interface changes common in mainstream browsers.

Nothing but very vague and useless marketing-speak.

Lookup PaleMoon and Basilisk in Wikipedia. The codebase of Goanna has diverged from Firefox / Gecko a lot, so trying to compare by versions won't tell you much. PaleMoon Goanna is regularly updated and supports nearly all the feature sets of a modern browser rendering engine and is feature compatible with Firefox / Gecko though it doesn't support webRTC - https://forum.palemoon.org/viewtopic.php?t=28182, DRM and webExtensions ... https://www.palemoon.org/technical.shtml

What you're looking for only makes sense for browser "forks" that just re-skin/layer on top of the latest releases of the main project. Basilisk is an actual fork which has lead development in it's own direction, i.e. they have features newer than the date/version of the fork but it's not because they rebased on the newer Firefox XYZ git and now have equivalence to that version.