Compressed archive of roughly 1.26 MB labelled SL410 with the codes GC2A-0622, GC1A and CG1B, which appear to be board or project identifiers for that model; the name does not explain them further. SL410 matches a Lenovo ThinkPad model, though the brand is not stated. The package most likely contains schematic or service material used to trace power rails, check signals and find components. Extract it with WinRAR or 7-Zip and confirm that the codes printed on the PCB match before trusting any reference designators.
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 @generalschematics. 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.