As the most upvoted comment in this thread is wondering what could be the motivations for that (and I'm also wondering), could you explain why you wished it exist?
Yes, me too. I've used void linux quite a bit which does use some BSD components like mandoc but is still gcc and GNU coreutils. I can understand the logic of using the packaging system from Alpine. I rather like pkg on FreeBSD, it feels more consistent, predictable and simpler than either deb/apt or rpm/dnf.
i did intend to use pkg at first, however, after some experimenting apk turned out to be the better option (there are things pkg still doesn't support - such as version constraints, getting it to work on musl is a fair amount of patching, its shlib scanning is semi-broken on Linux, and its repo indexing is insufficient for my purposes)
the shlib dependency stuff is pretty broken even in FreeBSD. apk is probably my favorite package manager experience. cool project, thank you