At 1.07 MB this PDF, coded SDLS153, is one of the larger datasheets in the series. The file name carries only a literature number, matching the Texas Instruments scheme for standard logic publications, and the described device is named inside. Expect pin assignments, function tables, switching characteristics and package drawings, possibly for several family variants. Technicians use it to check pin functions and supply limits during repair. Compare the chip marking with the listed variants before choosing a replacement.
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.