RAR archive for the Lenovo ThinkPad T420, marked NZ3 and UMA, meaning the version with integrated graphics only and no discrete GPU. Contents are not listed, but packages like this generally hold the system schematic. Unpack and check it carefully, since discrete-graphics T420 boards differ in their video section. Technicians use the drawings to trace power rails, check the charger, locate test points and identify components on shorted lines. Match the board number on the PCB before trusting 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 @alischematics. 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.