It can do a behavior-based check, including:
- How many users the note is @-ing.
- Whether the image is identical (or similar to, thanks to Misskey's usage of BlurHash!) to a known spam image
- Whether the note text has keywords linked to the spamming behavior.
- Non-admin Misskey users cannot delete notes.
- The note deletion API of Misskey is throttled to 300/hour.
MIT