Intel Flash Image Tool, release 15.0.21.1549, compressed into a 6.48 MB RAR file. FIT is the Intel engineering utility for assembling and modifying SPI images: flash descriptor, Management Engine region, BIOS and PCH strap configuration. In repair work it is typically used to rebuild a damaged ME region or generate a cleaned image from a dump read off the board. Check that the ME firmware in your dump reports a 15.0 version before loading it here. Verify the output size matches the physical flash chip before programming.
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 @mfittool. 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.