Add-ons
What other people wrote for Niles, from the add-on library. Each is a WebAssembly component in a GitHub release, and it runs in a sandbox with no database, no conversations and no other add-on's passwords. Niles shows exactly what an add-on may reach, in its own words, before you install it.
The same list is in Niles under Settings → Add-ons → Browse. Writing add-ons is the guide for publishing your own.
No add-ons yet. Publish one: the author guide.
A public repo with the GitHub topic niles-addon and a release appears here within a day. Publishing says how it gets listed.