Firmware image for the Apple A1237 MacBook Air, Apple code M82, logic board 820-2179, with 051-7273 also noted. SVT, as used in Apple's build-phase naming, is a pre-production validation stage. The image is written to the logic board's SPI flash with a programmer to repair corrupted firmware. Apple's 820-xxxx numbers identify the logic board itself, so check the marking on the PCB before writing. Back up the existing chip first, because it holds machine-specific data.
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 →