BUR #19643 has been approved by @nonamethanks.
remove alias posterior_cleavage -> butt_crack
I find it a little hard to believe anyone needs this alias for butt crack, unless you came straight from Sankaku. Though my main reason for proposing this is that typing "poster" into the search bar autocompletes to that as the first result instead of the poster tags, poster (object) and poster (medium). That, combined with the aforementioned questionable nature of the alias, makes me think it should be removed.
Updated