I think at this point its quite obvious that there is a list builder coming from Games Workshop for the new edition of Warhammer 40k. One that lots of people were using has been removed, with Games Workshop requesting the removal of this webapp due to an infringement of its intellectual property.
I saw this over on Miniwars first.
http://www.miniwars.eu/2017/06/generador-de-listas-para-8-edicion.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+Miniwars+%28miniwars%29
This was also the app I was using to explore lists. The final message from it's creator can be read here.
https://webapplications-webroster.rhcloud.com/rc/web/#!/rosterCreator