1337 immediately reminds me of 1337x.to which is a piracy website :)

Looks like the word means LEET or (Elite) within BBS forums (https://en.wikipedia.org/wiki/Leet) [I had wondered about why 1337x.to team named itself this and then asked AI to then get the reference and then searched it again on wikipedia to get to know more information/confirm it, saying this because I didn't know about this reference till today as I wasn't part of that era.]

if you know you know, if you dont know you are most likely B1ff :D