First up, wow! Great work on the migration to github actions!
I'm really looking forward to ditching travis. :)
As for REFERENCE.md
I get the sentiment, (generated things don't belong in repos), but I don't like the sound of option 1 or 3 personally.
90% of the time I read a REFERENCE.md it's via github, not via the forge.
We've also had several doc PRs recently where being able to review the changes to the REFERENCE.md was important.
I actually wish I could do that more often.
Are there any other options that might be viable? eg. Could we store the REFERENCE.md in its own branch that is auto updated on each merge to master???