In https://meta.wikimedia.org/wiki/Turning_off_outdated_skins when we killed five of the then-nine skins available on the site, originally these two were retained as unsupported-by-WMF because volunteers said they would keep them running and up-to-date.
However, this hasn't happened in practice. Various key features and extensions don't work, or don't work well, in these skins, including notifications, the visual editor, and others. Occasionally, someone shouts a lot (and rightly so), and WMF staffers and others try to apply a quick fix to keep things sort-of working, but it's against our explicit statement that we wouldn't do this, and it strengthens the incorrect understanding that we do try to keep them running.
Maybe we should admit reality, and remove them from production rather than falsely (albeit implicitly) claiming that they work by continuing to ship them?