RAR archive holding a BVR boardview for the iPhone 5S logic board, packed down to 56.7 KB. Once extracted, the .bvr file opens in boardview viewers that support the BVR format, letting you search a part designator, highlight a net and see every pad sharing it. Technicians use it to locate test points, follow power rails from the PMIC and pin down which capacitor is shorted to ground. Check the board revision and modem variant on your phone before trusting the layout, since Apple logic boards differ between models.
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.