In g10/textfilter.c a break with RFC 4880 compliance is outlined:
So, we default to the 2440 behavior, but use the 2440bis-12 behavior if the user specifies --no-rfc2440-text. The default will be changed at some point in the future when the mail clients have been upgraded.
Is this option and default behaviour still required?
It was rG07250279e7ec: * keyedit.c (keyedit_menu): Invisible alias "passwd" as "password". in 2004, which set default to rfc2440-text behavior.
And in 2007, the commit rGb550330067b6: * gpg.c (main): Disable --rfc2440-text and --force-v3-sigs by default. changed the default to no-rfc2440-text.
The option might still make sense, but the comment is now not accurate (requires the knowledge of history to understand).