The file name 163cmq gives only a part-style code with no device or board, so this 46.9 KB PDF is probably a datasheet for a dual Schottky rectifier family, despite the schematic label. CMQ-type codes are used for common-cathode Schottky pairs in power packages, and without a voltage suffix the document may cover several grades. Use it to check pinout, current and forward drop when replacing output rectifiers in switch-mode supplies. Match the marking on the part first.
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 @cyberlanelectonik. Enginerys does not host this file.
How to open a .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.