Zip archive holding a PDF titled Pinouts, version 0.2, classed as a schematic; the name does not state which device, board or connector set it covers. Pinout references list the pin numbers and signal names of connectors or chips, which helps a technician probe voltages, check a flex cable or wire a programmer clip correctly. Extract the PDF and read its header to learn what hardware it documents. Because it is an early version, cross-check critical pins against the board schematic or datasheet before applying power or soldering.
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 @boardview. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.