-If you don't specify --delete-during (--del) or --delete-after, the
-file deletions will be done before the first file is transferred.
-This is helpful if the filesystem is tight for space
+The --delete option may be combined with one of the --delete-WHEN options
+without conflict, as well as --delete-excluded. However, if none of the
+--delete-WHEN options are specified, rsync will currently choose the
+--delete-before algorithm. A future version may change this to choose the
+--delete-during algorithm. See also --delete-after.
+
+dit(bf(--delete-before)) Request that the file-deletions on the receiving
+side be done before the transfer starts. This is the default if --delete
+or --delete-excluded is specified without one of the --delete-WHEN options.
+See --delete (which is implied) for more details on file-deletion.
+
+Deleting before the transfer is helpful if the filesystem is tight for space