Merge 2caa4dd069 into 23ff7f1343

* Fix minor typo in content hash calculations

* Changelog

changelogs/client_server/newsfragments/2108.clarification

@@ -0,0 +1 @@
+"Public" rooms with respect to presence are defined through their join rule.

changelogs/server_server/newsfragments/2128.clarification

@@ -0,0 +1 @@
+Fix various typos throughout the specification.

content/client-server-api/modules/presence.md

@@ -68,5 +68,7 @@ will cause the server to automatically set their presence to `online`.
 
 #### Security considerations
 
-Presence information is shared with all users who share a room with the
+Presence information is published to all users who share a room with the
-target user. In large public rooms this could be undesirable.
+target user. If the target user is a member of a room with a `public`
+[join rule](#mroomjoin_rules), any other user in the federation is
+able to gain access to the target user's presence. This could be undesirable.

content/server-server-api.md

@@ -1337,7 +1337,7 @@ calculated as follows.
 The *content hash* of an event covers the complete event including the
 *unredacted* contents. It is calculated as follows.
 
-First, any existing `unsigned`, `signature`, and `hashes` members are
+First, any existing `unsigned`, `signatures`, and `hashes` properties are
 removed. The resulting object is then encoded as [Canonical
 JSON](/appendices#canonical-json), and the JSON is hashed using
 SHA-256.