diff --git a/Doc/library/email.contentmanager.rst b/Doc/library/email.contentmanager.rst
index bf917c84cdabf5..f4d162fd967caa 100644
--- a/Doc/library/email.contentmanager.rst
+++ b/Doc/library/email.contentmanager.rst
@@ -156,7 +156,13 @@ Currently the email package provides only one concrete content manager,
        :exc:`ValueError`.
 
        * For ``str`` objects, if *cte* is not set use heuristics to
-         determine the most compact encoding.
+         determine the most compact encoding.  Prior to encoding,
+         :meth:`str.splitlines` is used to normalize all line boundaries,
+         ensuring that each line of the payload is terminated by the
+         current policy's :data:`~email.policy.Policy.linesep` property
+         (even if the original string did not end with one).
+       * For ``bytes`` objects, *cte* is taken to be base64 if not set,
+         and the aforementioned newline translation is not performed.
        * For :class:`~email.message.EmailMessage`, per :rfc:`2046`, raise
          an error if a *cte* of ``quoted-printable`` or ``base64`` is
          requested for *subtype* ``rfc822``, and for any *cte* other than
@@ -191,13 +197,6 @@ Currently the email package provides only one concrete content manager,
        (distinguished from strings by having a ``name`` attribute), add the
        headers to *msg*.
 
-       Note that this method will append a newline character to the end of strings,
-       if it wasn't passed already. For example, the following are equivalent ::
-
-         msg = EmailMessage()
-         msg.set_content("hello")
-         msg.set_content("hello\n")
-
 
 .. rubric:: Footnotes