The docs and help output regarding colocation are wrong.
For example jj help git clone as well as https://jj-vcs.github.io/jj/latest/cli-reference/#jj-git-clone state, that the Git repo will be inside .jj, but that is only the case if you use --no-colocate, the colocation seems to be the default (at least now).
Same for git init to create a new repository or jj-ify an existing repository, it also by default creates colocated repos but the docs say otherwise.