Hello Robert,
This depends on the project structure.
If you have one main project that contains several submodules, git submodules
may be the most logical variant.
If you have several equal projects you would like to keep in a repository,
well, then repo from Android project is your friend, as
i mean, other than actual submodules, if one wants to lock a number
of git repos together with versioning, are submodules generally
considered adequate? i've heard a lot of dissatisfaction with
submodules, and a few people have recommended moving up to using
"repo" to accomplish the same thing.