List of file types compatible with Nextcloud

Is there a list of file types compatible with Nextcloud?
A friend of mine asked if they can upload / read .sla and .story files ?

Thanks :wink:

Did you read (and understand!) this: Mimetypes management — Nextcloud latest Administration Manual latest documentation ?
The topic is not quite as trivial as it seems at first glance. But once understood, one can adapt it to almost any need.

.sla files are basically xml files, so they could be opened somehow but a.f.a.i.k. .story files are text files stored in proprietary binary format, that would be a problem to read them on the web but uploading for sharing purpose is no problem.