Lqt-older and Lqt-newer

Have looked and looked and can't find where these two messages appear - Lqt-older ("older") and Lqt-newer ("newer"). Can anyone tell me whether these messages refer to 1 older (or newer) something or more than 1 older (or newer) something? And what is the something referred to - is it an edit?

Seem to be unused.

Should we remove the messages, or consult the devs?

 Done I removed the messages in mwr:79996.