One thing that seems to be common amongst many of these Firefox forks is they're very difficult to find which official version they're equivalent in functionality to. This one is no exception.
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.
PowerFox is both standards compliant and feature-rich, supporting the latest web technologies to ensure compatibility with modern websites.
which means.. next to nothing. No "PowerFox version X has (at least) the same web standards support as Firefox Y".
it likely has code from newer versions spliced in
That's a good thing, but making it clearer what to expect will make it easier for potential users to decide whether to give it a try.
There are not that many options for the potential users.