Trivia: While it's not explicitly stated, the Superman from another earth played by Brandon Routh is the one from Superman Returns (and by extension that from the original Superman movies). Aside from the obvious factor of the same actor, he name checks his son Jason, which is what his son with Lois was called in that movie too. His reference to fighting himself relates to Superman 3.
Crisis on Infinite Earths: Part Two - S1-E9
Trivia: The version of Batman played by famous Bat-voice Kevin Conroy is a darker version of that from the graphic novel The Dark Knight Returns. The line "the world only makes sense when you force it to" is a version of a line from that comic (also used in Batman V Superman), also "Clark always said yes to anything with a badge or a flag." There are also elements from Batman Beyond, which first aired in 1999 (hence Earth-99), in which Conroy voiced an older Bruce Wayne mentoring a new Batman. The whole scene is full of nods to other versions - describing Kryptonite as "a little souvenir from the old hometown" is a Lex Luthor line from the original Superman movie, and him describing Superman as "strange visitor from another planet, with powers and abilities far beyond those of mortal men" comes from Superman serials from the 40s and 50s.
