Very small RAR archive, only 116 KB, labelled for the Apple iPad Pro 12.9. The name does not say which generation or what the archive contains, and the tiny size suggests a single compact file, perhaps a boardview or partial document rather than a full schematic. Open it to confirm. Material like this is used to locate components and test points on the tablet logic board. Since several iPad Pro 12.9 generations exist, check the model number and board markings before relying on it.
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 .rar file
Compressed archive — the usual wrapper for a schematic + boardview pair or a BIOS + EC set.