git - What does this green icon mean in a github repository?

Question

What does this green icon mean in Github? I know the commit link takes me to another repository. I need to do something similar. Is this a symlink? Or a submodule? Being still somewhat new to git, I'm wondering how I can replicate this myself. Once created, how do I update this external dependency?

Answer 1

This is a submodule: a link to a specific commit in another repository at a different URL. The repository will be cloned when git submodule update --init is run, and then the referenced commit (784fd39) will be checked out.

You can create submodules using git submodule add <url> <directory>, which will add a submodule reference for the given URL at the directory you specify, in the current working directory.