GitHub supports some git (commit) trailers, although it doesn't call them as such, for instance it supports Co-authored-by:, which has to be separated by two blank lines from the commit message for GitHub's purposes. (I'm not sure if git commit --trailer adds those blank lines, by the way.)
There are apparently more such as Relates-to: [#12312312], but I'm not entierly sure the latter is treated anymore magic by GitHub that if you were to include the #12312312 anywhere else, meaning it might create a link in any context.
Is there a complete reference list of such trailers supported by GitHub, meaning that they do something noticeable on GitHub, documented somewhere?