tl;dr version: please don't look at this repo for updates to the squeak-vm Debian package.
These are two independently maintained repos. The squeakvm.org repo your link points to is for the legacy VM (i.e. what currently exists in the squeak-vm Debian package and will remain so going forward - this is the one you want) and this repo is for the newer, high performance VM (i.e. what I am working on packaging up for the opensmalltalk-vm Debian package). While they are conceptually similar VMs, they are very different implementations, separate codebases with different maintainers. That's why we want to create the opensmalltalk-vm Debian package as the repos/VMs will not be merging but both are relevant to Smalltalk users as they run different Smalltalk image files. (i.e. the users data)
I wouldn't blame you for being a bit confused by this as even Smalltalkers get confused by it from time to time!