Datasheet marked with the Texas Instruments document code SDLS110, part of the series TI uses for its classic TTL logic devices. The name does not reveal the specific chip, so open the 247 KB PDF to see which part and packages it covers. It should provide pin assignments, logic functions, supply requirements and AC timing. Those details are needed to probe a suspect IC in circuit, to read the board around it, and to choose a suitable replacement when servicing older digital equipment.
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.