Currently we add banners to the wiki spaces of retired projects. However, they remain in the main spaces listing, which clutters the list.
It's possible to archive spaces [1] AFAICT this does not affect any URLs, but does move them from the main list to the archived list. I think we should start archiving retired wikis to free up the main list. WDYT? Sebb [1] https://selfserve.apache.org/confluence-archive.html
