User blog comment:DeCastilane/Earth-712/@comment-5448995-20160420223422/@comment-16461120-20160421164255

In terms of a specific reference, it's the bottom of the second page of where a narration box for Zarda Shelton (Earth-21195) posing as Zarda Shelton (Earth-712) identifies the reality as "(Late) Earth-712", indicating that it's dead and gone.