The OP is not referring to the bitcoin code, he is referring to "issues / PRs / gists / pages" on the bitcoin repo on github.

If someone identifies a problem with the bitcoin code, they will open an issue, and if someone upgrades (or changes) the code in some way, they will open a pull request to be reviewed (and if approved) and merged by the maintainers of the bitcoin repo.

Major vulnerabilities should be reported privately, and collaboration on major upgrades are done are likely done outside of github among the maintainers.

I do think the OP has somewhat of a point. If the /bitcoin repo is not backed up regularly, any bug reports and bug fixes not yet fixed/implemented respectively will need to be resent to the maintainers via an alternative means.