i maintained a system where for .. reasons (like other systems) from early days have users with id: null "null" "" and some i do not even know how to write here
so probably early bird
His oldest repository was updated in 2011. Looks like he's been there a long time.
It's funny, i actually worked with this guy (same small startup, not closely), and recognized him from that unique username on this post. It's been so long i wouldn't have had any idea if not for the oddness of the single letter username.