Interesting! It seems some of Scalar from late 2021 has already made it into the official git project's contrib dir [0]. It looks like Scalar is mostly an opinionated way to configure git [1] using git partial-clone among other features.
Git partial-clone looks almost perfect, except it only downloads and displays files explicitly added to the git sparse-checkout list. I want some "magic" vfs shenanigans that lets me view and browse the full repo exactly as if the full repo where checked out, but when I open a directory or file the contents are downloaded on-demand.
It seems win32 has specific support for this kind of tech at a couple different layers, one that's low level filesystem virtualization that's like FUSE I guess [1], and another that's higher level and exposes sync status of files via explorer and other win32 apis [2] which is what I assume OneDrive, Dropbox, Google Drive, etc use.
It supports neat stuff like partial clone which seems like a pretty big deal.