According to the FAQs, questions are on topic when they are about:
- Jewish law or practice (what to do or why)
- Jewish philosophy
- a Jewish text (explaining a passage)
- history of Judaism
- language used in Judaism
- general knowledge (science, etc.) as it relates directly to Judaism
Yet questions questions unrelated to Judaism, even if they are about...
- other religions
- Hebrew language
- Jews, Jewish history, and Israel
are off topic.
So questions about the history of Judaism are on topic, whereas questions about Jewish history are off topic.
NOTE: I am not encouraging a change in policy whereby questions "about the Hebrew language or about history or news of the Jewish people, Jewish individuals, or the State of Israel, except as related to Judaism", will be considered on-topic.
Rather, I am encouraging that the FAQs be edited to clarify that questions about "the Hebrew language or about history or news of the Jewish people, etc." be clearly identified as off-topic.
I don't know if this is a recent edit to the FAQs, or was always like this.