RAR archive of about 851 KB labelled Intel PEB-7710VLA-R2, which reads as a board model with revision R2. The name does not say whether it contains a schematic, manual or BIOS, so inspect the contents. Documentation for an embedded or industrial board like this is typically used to identify connectors and jumpers, trace power circuits and locate components when diagnosing faults. If a firmware image is inside, back up the existing chip first and confirm the image size matches the flash 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 @cyberlanelectonik. 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.