english original missing
In the translation editor for MediaWiki:Categorywatch-emailbody/en the English source message is not shown, although the translations in the assistant languages are. This is the only message having this problem that I have found this afternoon.
Obsolete messages show up in search results all the time. The signs of obsolescence are not obvious to the non-initiated. Since your policy is not to clean them up, perhaps there should be an indication on the edit page or window that a message has been deactivated for translation.
In which use case do obsolete messages show up all the time? The only thing I can think of is in TM results. And that's exactly where we want to keep them for a while.
I came across this message when reviewing recent changes to cy - user Xxglennxx had changed this message. I imagine that he had run a search for the word 'gwylio' - there is a whole batch of changes related to this word.
When searching for any keyword using the search box at the top left, obsolete messages containing the keyword in question will show up in the search results the same way current ones do, with no way to distinguish between them from the results list.
You can distinguish them on the translation page itself by the absence of an English original (and in the classic/non-Javascript editor, by the absence of the "In other languages" link at the left), but for most users, this is confusing and clarifies nothing.
I do agree with keeping obsolete messages. They are useful for translation memory purposes if nothing else. But I think it would be good to have some clear way of distinguishing them from current messages, in search results and in the edit pages themselves.