I’ve found this 5 year old answer that almost answers my question, but not quite.

My git repo contains several submodules, many of which contain submodules themselves.
I want to be able to run git submodule update --init --recursive to easily initialize the entire environment.

The downside is that boost is in there somewhere, which has 150+ submodules itself, of which I only need 2.

I can’t for the life of me figure out how to exclude submodules from a single nested submodule.

When I run git -c submodule."lib/boost".update=none submodule update --init --recursive it just skips boost, but I don’t want to skip boost: I want to init/clone/pull boost and two of its submodules (container and lockfree)

I can’t omit --recursive because then I’d have to explicitly add all of the other submodules, which are a lot.