ZIP archive for a Dell board numbered DAVM8NMB6D0, a Quanta-style designation, tagged OK, which usually means the uploader considered the contents working. The name does not say what is inside, but at 647 KB it most likely holds a firmware dump or small boardview rather than a full schematic. Quanta builds many Dell motherboards and codes them in this DA-prefixed format. Extract it and inspect the files first; if it is a BIOS image, back up the original SPI chip before programming and confirm the image size matches the chip.
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 @ITHINKHS. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.