Great project that deserves all the funding it can get.
DivestOS is second only to GrapheneOS (from what I can tell, at least), Mull is a fantastic hardened Firefox fork that barely trails behind with updates, and... well I don't know much about his other apps, to be honest.
But those two projects alone are invaluable to the Android privacy and FOSS community.
As a Graphene and Mull user, I can only say it's surprising and a little sad the security/privacy and copyleft don't overlap as often as they should (which is all the time).