Datasheet in PDF form, 175 KB, for the 74AHC1G00, a single two-input NAND gate from the 74AHC logic family in a small package. Though indexed as a schematic, it is a component reference document describing pinout, supply range, logic function and package markings. Technicians use it to check a suspect gate on a board, confirm which pin is the output, and find a compatible replacement by matching marking code and package type before 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 @one5technology. 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.
Any PDF readerSumatraPDFFirefox / ChromeFlexBV (links PDF to boardview)