I saw that this question: Einstein's initial clue that spacetime is curved being flagged as off-topic, as it belongs on History of Science SE. However, there is a tag here for 'history' and it seems that historical questions have been accepted here in the past.
Presumably, the situation has changed because that other SE site was created more recently? So, are history questions no-longer on-topic here? If so, I assume we won't be mass-migrating existing questions under the 'history' tag to that site; however, should we consider updating the tag description for 'history' to make it clear it is now a defuct category?