Texas Instruments datasheet filed under literature number SDLS139, a 257 KB PDF. The name gives only the TI document code, not the part, so open the cover page to confirm which logic device it covers. SDLS-prefixed documents belong to TI's legacy bipolar TTL logic families such as standard 74, 74LS and 74S. Use it for pinout, truth tables, supply limits and switching characteristics when replacing or probing a chip, and check that the full marking on the package matches.
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.