ASRock Z370 Extreme4 desktop motherboard BIOS, stored in a RAR archive and listed as a 16MB image, which suits a 128-megabit SPI flash chip. A dump like this is used to recover a board that fails to post after a bad update or a corrupted firmware region, by writing it with a CH341A or similar programmer. Dump and save the current chip contents first, since they may carry the board MAC address and serial. Check that the chip on your board is 16MB and the model really is the Z370 Extreme4.
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 @biosarchive. 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.
Back up your own chip before writing any dump, and match the full board number and revision. Flashing guide →