{{msg-mw|Loginsuccess|notext=yes}}
Should be able to use GENDER for the username, for example necessary in French.
This already works. LoginForm::displaySuccessfulLogin() always has the logged on user name as a parameter and uses $wgOut->addWikiMsg which processes magic words.
Only Loginsuccess ("<strong>You are now logged in to {{SITENAME}} as "$1".</strong>") is fed into displaySuccessfulLogin() in core and svn extensions.
Looking at the translation hint, that's been in since 16 March. What do we have the hints for anyway of they are not read?
I only checked the link that Raymond gave me here. Is there some list for other pages besides those that support GENDER.