[Docs] Documented AppPlugins

src/octoprint/plugin/types.py

@@ -1058,6 +1058,28 @@ class ProgressPlugin(OctoPrintPlugin):
 
 
 class AppPlugin(OctoPrintPlugin):
+	"""
+	Using the :class:`AppPlugin mixin` plugins may register additional :ref:`App session key providers <sec-api-apps-sessionkey>`
+	within the system.
+	"""
+
 	def get_additional_apps(self):
+		"""
+		Overrides this to return your additional app information to be used for validating app session keys. You'll
+		need to return a :class:`list` of 3-tuples of the format (id, version, public key).
+
+		The ``id`` should be the (unique) identifier of the app. Using a domain prefix might make sense here, e.g.
+		``org.octoprint.example.MyApp``.
+
+		``version`` should be a string specifying the version of the app for which the public key is valid. You can
+		provide the string ``any`` here, in which case the provided public key will be valid for all versions of the
+		app for which no specific public key is defined.
+
+		Finally, the public key is expected to be provided as a PKCS1 string without newlines.
+
+		Returns:
+		    list: A list of 3-tuples as described above.
+		"""
+
 		return []