Greasy Fork is available in English.
GitHub Dark in userscript form, with a settings panel
< Rückmeldungen auf GitHub Dark Script
This was fixed yesterday. Please use the force update if you're still seeing this problem.
Also, you'll get a quicker response, or see if the issue as already been reported and/or fixed, check our GitHub issues. In this case, see https://github.com/StylishThemes/GitHub-Dark/issues/793
Title section styles changed and broke