Since flow/neos gerrit will be shutdown at the end of this year and people are advised to move their changesets to github (Move your open Gerrit changes to GitHub pull requests - now!), I still found some other things that should be moved/migrated:
forge issues and their discussions: There are quite some discussion gems like e.g. https://forge.typo3.org/issues/53080 that should be saved. There is a tool to migrate redmine issues to jira (https://confluence.atlassian.com/jira/importing-data-from-redmine-313459706.html), but as @bwaidelich already stated, we probably don’t want all issues migrated. There is a (html) backup of the forge issues available at http://cognifloyd.github.io/neos-historical-redmine/ so at least the discussions aren’t lost.
When/how should we tackle this?
the flow cookbook: https://wiki.typo3.org/Flow_Cookbook any alternative on where to keep this? Maybe create a (sticky?) discuss topic here?
If you have anything else in mind that is relevant just keep adding to this list.