Compressed package of 2.08 MB carrying the code 3CESL-RH-12, which suggests revision 12 of the 3CESL RH series. The name gives no brand, device or file type. Treat it as unidentified until the extracted files show what they are. Typical archives like this hold a firmware image plus notes. Match the version and any board identifiers with your hardware. Back up the original flash before writing anything, and check that the sizes match.
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 @schematicslaptop. 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.
7-ZipWinRARThe Unarchiver (macOS)