Btw, I worked at GitHub for 3 years and they are very aware that slowness is a big issue throughout the whole product. There was a year long cross team effort to improve things but the main goals were not achieved IMO and it shows.
Good question. I don't have now right now but I can prepare one soon. In any case I store zero information from users. When you are logged in traffic goes directly from your browser to GitHub.
This comes to solve the problem of the terrible UX in the most widespread git service. I won't dare to try to convince my whole team, or company, to migrate to GitLab, but this can be easily adopted.