-Without this option, all existing files (including updated files) retain
-their existing permissions, while each new file gets its permissions set
-based on the source file's permissions, but masked by the receiving end's
-umask setting
-(which is the same behavior as other file-copy utilities, such as cp).
+When this option is em(off), permissions are set as follows:
+
+quote(itemize(
+ it() Existing files (including updated files) retain their existing
+ permissions, though the bf(--executability) option might change just
+ the execute permission for the file.
+ it() Each new file gets its permissions set based on the source file's
+ permissions, but masked by the receiving end's umask setting (including
+ the stripping of the three special permission bits).
+))
+
+Thus, when bf(--perms) and bf(--executability) are both disabled,
+rsync's behavior is the same as that of other file-copy utilities,
+such as bf(cp)(1) and bf(tar)(1).
+
+dit(bf(-E, --executability)) This option causes rsync to preserve the
+executability (or non-executability) of regular files when bf(--perms) is
+not enabled. A regular file is considered to be executable if at least one
+'x' is turned on in the source permissions.
+
+quote(itemize(
+ it() To make a file non-executable, rsync turns off all its 'x'
+ permissions.
+ it() To make a file executable, rsync turns on each 'x' permission that
+ has a corresponding 'r' permission enabled.
+))
+
+If bf(--perms) is enabled, this option is ignored.