On the second page of the repo list of the openHAB organization there are a few repos, that are clearly outdated: https://github.com/openhab?page=2&utf8=✓
While for most of them the possibility to create issues is blocked, it’s still possible to open PRs. In Github you can archive such repos, so everything there is read-only and it’s clearly visible, that they are archived: https://help.github.com/en/articles/archiving-repositories
Good idea! I wasn’t aware of this Github feature yet (seems to be fairly new), so thanks for pointing me at it. I’ve archived all repos that are only kept for history, but which aren’t in active use anymore.