Git: "Your local changes to the following files would be overwritten by checkout. [...]
Please commit your changes or stash them before you switch branches.
Aborting"

Fucking nitpicking, that's not "Aborting", that's meant to be:
"Dear user, would you like to overwrite your current changes, even more so as you are currently in a so-called detached head state anyway, as you obviously just checked out an old tag to try a temporary rebuild of an old project state."
Yes, the build targets are checked in, as this can be very useful in some scenarios.
It's just! some! CSS! from the SCSS!
Stop "Aborting"!