Gigabyte B550M DS3H AC boardview covering revisions 1.0 and 1.1, delivered in a 787 KB rar archive. B550 is the AMD chipset named in the model, and AC marks the variant with onboard Wi-Fi. Check whether your board reads 1.0 or 1.1 on the PCB, since the archive may hold separate layouts or one shared file. Use a boardview program to locate VRM parts, the BIOS chip and test points, and to trace power rails when a board shows no power or no display.
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.
7-ZipWinRARThe Unarchiver (macOS)