Git submodules is a way how to split the repository into logical segments.
Git configuration is stored in root of the application in file ".gitmodules"
How do I get documentation that is compatible with my git?
git submodule --help
git submodule add -b master https://Subscription.visualstudio.com/PathToGitRepository SubDirectory
Everyone makes mistake and therefore here is how you can remove the submodule
git submodule deinit -f SubDirectory