Each tribble belongs to a subspecies. Various subspecies can be fed different food items to breed different kinds of tribbles. The words after the tribble are just an abbreviated version of their subspecies name, which is usually the last name of a Cryptic team member (for example, there is a Stahl tribble, but it shows up as Stah)
They always had the subspecies listed under 'info', but several months ago they were updated to display the name, presumably to make it easier to identify them on the exchange or elsewhere.
They could always change them. They have the power. Just feed a STAL tribble (one of the most common) a good hunk of Delavian chocolate and it becomes the DSTAHL tribble. Upon activation it performs the Death Blossom. (for those of you younger than 20 that would be from The Last Starfighter)