ASUS B150M-C D3 repair guide, a 1.25 MB RAR archive for the DDR3 memory variant of the B150M-C board. Confirm the D3 marking on the PCB, since the DDR4 version and the D620MT OEM board differ. The guide is meant for stepping through standby power, the startup sequence and key voltages to isolate no-power or no-POST faults. Revision is not stated, so check the PCB. Any RAR-capable extractor opens it; the inner file types are not listed.
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 @ZINFOSERVICECHANNEL1. 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.
7-ZipWinRARThe Unarchiver (macOS)