I have those phrases in my stock vbulletin, they exist in my phrase manager and yes are in user tools (global).
However no where in any templates can I find them being used.
It's possible they are used in a php file, not a template... or maybe old phrases from earlier vBulletin version not used anymore.
LOL at documentation, I don't deal with that. There's the manual but I doubt it will be of much use.
I would look in functions.php file at:
Code:
function init_language()
That function builds the $vbphrase array.