Archive for the HP ProBook 450 G1, labelled as a Wistron design dated 2013, so it is most likely a schematic packed in RAR form. No board number or revision is given in the name, so you will need to check the title pages after extraction. A circuit diagram like this lets a repair technician trace rails from the charger and power controller to the CPU and memory, and locate fuses, MOSFETs and test points. Confirm that the motherboard markings match the document before replacing parts or measuring against the reference voltages.
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.