A logic datasheet with the document code SDLS157, delivered as a 286 KB PDF. The name gives no device number; SDLS codes are used by Texas Instruments for its standard logic data sheets, and the covered part is printed in the header. Expect a pinout, truth table, recommended operating conditions and package details. This is the reference to have open while probing gates or buffers for stuck levels. Verify the marking on the physical chip matches the document before trusting the pin assignments.
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 @datasheet_technar_org. 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.