DOCSP-48242-mongosync-metadata-post-sync (mongodb#651)

* DOCSP-48242-mongosync-metadata-post-sync

* capitalize heading

* reviewer updates

* clarification

Author: amalhotra-mdb

source/reference/mongosync/mongosync-behavior.txt

@@ -281,6 +281,18 @@ Rolling Index Builds
 
 .. include:: /includes/rolling-build-limitation.rst
 
+``mongosync`` Metadata
+~~~~~~~~~~~~~~~~~~~~~~
+
+``mongosync`` stores its metadata in a database or multiple databases 
+during migration. The metadata databases can be named any of the following: 
+
+- ``mongosync_reserved_for_internal_use``
+- Anything beginning with ``mongosync_internal_``
+- Anything beginning with ``mongosync_reserved_for_verification_``
+
+You should drop any metadata databases after a successful migration. 
+
 Destination Clusters
 --------------------