In December 2018, Tiago Botelho hosted a [Deep Dive] on GitLab's [Pull Repository Mirroring functionality] to share his domain specific knowledge with anyone who may work in this part of the code base in the future. You can find the [recording on YouTube], and the slides in [PDF]. Everything covered in this deep dive was accurate as of GitLab 11.6, and while specific details may have changed since then, it should still serve as a good introduction.
