A peek at where the refs are kept might help understanding, even if,
as the DESCRIPTION section suggests, direct access is not part of the
public API.
Balance that out with a pointer to update-ref.
Suggested-by: Geoff Russell <geoffrey.russell@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>