A 223 KB PDF datasheet named only by a Texas Instruments SDLS literature code, the numbering TI applies to documents for its standard TTL logic lines. The specific part number is not in the name, so the first page has to be checked to identify the device it describes. Such sheets give pinout diagrams, truth tables, recommended operating conditions and propagation delays, which are needed when tracing logic faults or picking a substitute. Match the chip marking on the PCB with the document before swapping components.
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.