Boardview in BRD format for a board labelled AT6-D, in a 166 KB RAR archive. The name gives no brand, model or revision, so identifying the matching hardware depends on the AT6-D marking on the PCB. BRD boardviews open in OpenBoardView, FlexBV and similar tools, where you can search components, highlight nets and find test points when tracking a short or missing rail. Check the board marking carefully before relying on any part placement.
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 @boardviewsandachematics. 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)