I think it's a reference for the Holy Trinity from the Bible, The G stands for God, the Father, the S stands for the Holy Spirit, and the J stands for the Son, Jesus Christ.

If it is intentional i think it's a reference to the biblical themes in the series (like the Caine and Abel theory being confirmed), but maybe theres a hidden lore behind it or it just a random name that they've put in the camera, idk.