The purpose of this save file is to have a somewhat legit-looking living dex (i.e. Note: once opened in PkHeX, some of the Pokemon will be tagged as 'illegal' - this is simply a bug in PkHeX, just open the Pokemon, validate it and it will show up as legal.
This save file features a complete Living Dex (1-807 + Alolans) for USUM.