Archive for the Apple iPhone XS Max, 4.19 MB in ZIP form; the suffix in the name suggests a duplicate copy of the same package. The file name does not list its contents, but iPhone archives of this size typically contain a schematic, a boardview or both for the stacked logic board. Technicians use them to follow PP_ power rails, measure diode values on connectors and locate components between the two board layers. Make sure the board variant you are repairing matches the drawings before trusting pin numbers.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @cyberlanelectonik. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.