Merge pull request #2754 from matrix-org/travis/ll/clarification

Attempt to clarify how the `state` restriction works for lazy-loading

api/client-server/sync.yaml

@@ -42,12 +42,15 @@ paths:
         full state of rooms is requested, to aid discovering the user's avatar &
         displayname.
 
-        Like other members, the user's own membership event is eligible
+        Further, like other members, the user's own membership event is eligible
         for being considered redundant by the server. When a sync is ``limited``,
         the server MUST return membership events for events in the gap
         (between ``since`` and the start of the returned timeline), regardless
-        as to whether or not they are redundant.  This ensures that joins/leaves
+        as to whether or not they are redundant. This ensures that joins/leaves
         and profile changes which occur during the gap are not lost.
+
+        Note that the default behaviour of ``state`` is to include all membership
+        events, alongside other state, when lazy-loading is not enabled.
       operationId: sync
       security:
         - accessToken: []

changelogs/client_server/newsfragments/2754.clarification

@@ -0,0 +1 @@
+Clarify the behaviour of ``state`` for ``/sync`` with lazy-loading.