It's only on DockerHub, though. Pushing to GitLab failed.
FROM scratch
, copy that directory into the image and only as a last step layer the operating system on top. The initial layer containing nothing but the historic TeX Live will be perfectly deterministic (by virtue of being frozen) so you get perfect layer reuse and OS updates on top can be done in a matter of seconds.
TL<YEAR>-historic-tree*
tags are those that contain only the TeX Live trees (for Linux x86-64). We have not publicly announced the names yet but probably they will stay as is.
matrix
entry more in the CI file. And as I said, the update strategy as per the other issue would be orthogonal to that split.