I'm not a security expert but I do know that the Homebrew is working with openssf on security: https://openssf.org/blog/2023/11/06/alpha-omega-grant-to-help-homebrew-reach-slsa-build-level-2/
Boxkit predates wolfi so it's still alpine, I'll probably replace it at some point but most of the forks of boxkit are because people want the premade github actions and they end up replacing it with whatever distro they want anyway. The wolfi connection is because I know the people who work there (including a ublue maintainer) and we have similar goals/ideas on how linux distros should be put together. My ideal dream is a wolfi userspace systemd-sysext on top of fedora base, then we can have our cake and eat it too!
We're not security experts but lots of us work in the field and that gives us access to peer review from experts when we set things up. We sign every artifact with sigstore so users can verify that the code used in github is what's on their image, that sort of thing. And most of our practices utilize CNCF governance templates that lots of other projects use.
bluefin co-maintainer here. espanso is a hard one, we have an open issue on getting it to work because it'd be something awesome to include. We might end up needing to package it but haven't had a chance to look deeper into the issue.