+* server - Use "server:hostname" to search for posts from a specific server. In the case of group postings, the search text contains both the hostname of the group server and the author's hostname.
+* source - The ActivityPub type of the post source. Use this for example to include or exclude group posts or posts from services (aka bots).
+ * source:person - The post is created by a regular user account.
+ * source:organization - The post is created by an organisation.
+ * source:group - The post is created by or distributed via a group.
+ * source:service - The posts originates from a service account. This source type is often used to mark bot accounts.
+ * source:application - The post is created by an application. This is most likely unused in the fediverse for post creation.