Boardview for the iPhone 6S Plus, a 323 KB file in BVR format. No board number, revision or modem variant is mentioned, only the model abbreviation, which reads as 6S Plus. Technicians load it into boardview software to find components by reference, follow nets between connectors and ICs and pick spots for voltage or diode readings. It is useful when diagnosing a shorted line, a touch or backlight fault or missing power rails. Confirm that the logic board is the 6S Plus rather than the standard 6S before trusting part positions.
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 @GENERAL_SMART_PHONE_SCHEMATICS. Enginerys does not host this file.
How to open a .bvr file
Text boardview from the BoardView R family of tools, seen for Lenovo, MSI and Clevo boards.