This affects multiple sourcehut sub-projects (I've noticed it in commit messages on builds.sr.ht and readme.md's on hub.sr.ht and git.sr.ht):

When multiple underscores are used inside of a word, they are used for emphasis. While this is what the original markdown does too, most renderers I've seen deviate from it and CommonMark also specifies this deviation. I find it rather annoying to have to escape underscores in project_names_with_underscores and such, so would appreciate it if sourcehut could adopt CommonMark or otherwise change this behaviour.