An archive of repair files. Shared as “MST_EXT_SPI #ISP_20210625_94058.7z” — a .7z file, 2.95 MB.
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 @led_software. Enginerys does not host this file.
How to open a .7z file
High-ratio compressed archive, often used for large BIOS collections.
7-ZipWinRARKeka (macOS)