Gigabyte boardview for the GA-B150M-HD3 DDR3 motherboard, revision 1.0, with a WP tag in the name, delivered as a 1.14 MB RAR archive. The DDR3 marking distinguishes it from DDR4 versions of the same model, so matching the exact variant matters. Inside is a layout file for boardview software, used to locate components and test points, follow nets and trace VRM or memory power faults. Check the model, memory type and revision printed on the board before working from it.
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 @BoardSchematic. 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.