[Portal] "J Print" Easter Egg

I did another Portal playthrough, but I was aware of my surroundings for the fist time. I explored every part of the level and used the "mat_fullbright 1" command on dark places and I found this "easter egg". If you have any ideas on what could this mean, let me know in the comments. And please subscribe to my channel of you are liking the content.
Also, I don't know why some parts of the text got cut out on the right. Hopefully you can still understand what I've written!
I'm also sorry for the very loud audio. It will be better in the next clip!
#Portal

[@therealfrapsed]

Okay, so I found out that @Ossy Flawol did find this before me while watching his portal iceberg video. I didn't see the video beforehand and this was a coincidence.

[@Slavic_boi]

Very cool bro

[@therealfrapsed]

@@Slavic_boi ty bro 😌

[@jod422]

i doubt its johnson bc cave wasnt in the lore at all when portal 1 came out

[@therealfrapsed]

I don't know that it isn't Cave Johnson but I know for sure that he was in the game's lore back then.
If you go to the Rattmann den in the 17th chamber, you can find a username and password hidden behind a detached security camera which can be used to access the old aperturescience.com website (you can do that now with the Wayback Machine).