2 translator notes this time, when people mention "K" or any other letter "University" it means the school starts with that letter, but they don't want to mention the real name. For this case, since this manga's about a bunch of criminals, they don't want to slander the school
Second is the Employment Ice Age. It was a time from the 90's to the 2000's in japan where employment stagnated and new graduates couldn't find any jobs. That lead to a lot of those people becoming hikikomori, a spike in suicide rate, and also was the tipping point that started japans declining birthrate.