RAR archive for the Dell Latitude E7250 on Compal board LA-A971P, with CD3301 mentioned in the name; the contents are not listed, so open it to see whether schematics, boardview or firmware are inside. Compal builds many Dell Latitude boards under its LA-xxxxP numbering. Material like this helps trace power rails, locate parts and diagnose no-power or no-charge faults. Before relying on it, compare the LA number and revision printed on your motherboard with the file, since Dell often uses several board variants per model.
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 @fixtronix. 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.