Before now, we have excluded conlangs from our scope, but Esperanto is on a whole different level. For example, it has native speakers.
If Esperanto will be considered on topic, questions about it will still need to fit the other rules:
No usage/grammar questions if they're not focused on the Linguistics aspect;
No tips for learning the language;
It fits the point #7 in the FAQ that states:
Questions about a single word/single language. We decided to set such questions on topic, because they can bring up interesting facts, but with certain conditions. (1) The user provides evident research effort in their questions. This way we'd help you regardless of the difficulty of the question. :) (2) The question is more focused on the Linguistics aspect rather than the Usage one, because in that case it'd get off topic.
Any other rules in the SE sites or our FAQ.