Asked the dev about this, and got a reply that I thought somebody else might find useful.
ForkLift supports URL schemes of the format:
where everything following the :// is the UUID of the “Favorites” item in ForkLift. The UUID isn’t exposed in the interface, but it’s in the file:
Easy enough to find if you really want it. Personally, I’m dropping ForkLift URLs into associated project folders so I can get to it easily from Finder for web projects.