Three codes were hidden in the HTML source of the ARCHETYPAL VISIONS – 4 post on the Investigate Ingress blog.
[1] daixicul43u39r5ce
[2] aa6or4wr7goetlg4l
[3] x56qs8sk23ex9pnft
Code #1, #2 & #3
Observations
Each code have 17 characters and if you count the total amount of digits you get 15. They all work together.