RAR archive of 10.3 MB for the Samsung Galaxy Note 20 5G, model SM-N981U, the US version of the phone. Exact contents are not stated in the name, yet a package of this size typically holds schematic pages and possibly component-placement drawings for the stacked mainboard. Technicians use them to follow power rails, identify PMIC outputs, locate test points and check suspect lines for shorts. Extract with WinRAR or 7-Zip, and confirm the model code and board revision match the phone before relying on any values.
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 @esquematicosparatodos. 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.