This is the DC Universe proper as it appeared at the end of Infinite Crisis. It is where the vast majority of DC Comics are set including Justice League of America and Justice League: Generation Lost.  It is more or less the same as the usual post-Zero Hour (1990s) DC Earth, but a number of the 1980s and 1990s retcons were undone. These included the Man of Steel origin for Superman, Wonder Woman’s absence as a founder of the JLA, and that Batman never caught his parent’s killer. The name was inspired partially by the old pre-Crisis on Infinite Earths Earths (where the prime Earth had been Earth-2 in the 1940/50s and Earth-1 during the 1960-80s) and by the reformation of the DC Universe during the 1990s Zero-Hour crossover.