To get on the list for the Endgame closed beta you have to donate $5 or more to support the Cahokia Mounds and tag that donation with "#AncSoc". When you get the invitation, I would recommend joining the Cahokian line for a couple of reasons.
This is the link to donate: http://www.gofundme.com/cahokiamounds
The link was where the original info was provided: http://www.AncientSocieties.com/action-save-cahokia-mounds/
One person's translation (not mine) was:
Truth Past Truth Present Civilization - the truth of the past still applies today [my note: what about "Civilization"?]
Conflict Courage Strong Victory Reincarnate - the winning faction will be reincarnated [in Endgame]
Weak Lose Die Destroy - the weaker faction will die and be destroyed
Rebel All Die - if you choose not to go along, everyone will die.
The gist is that the stronger faction will get transitioned to Endgame, retaining AP and badges, etc. The weaker faction won't. I wanted to replace "faction" with "player" but ran into trouble translating it that way.
For example, I'd like to translate the last line as Any Player who refuses to transition from Ingress to Endgame will die (they'll lose their AP and badges? or just stop working?). But "All" comes after "Rebel", so how would you read it?