A 176 KB PDF catalogued as a schematic, named 28LV64, a part number from the low-voltage 64 Kbit parallel EEPROM family. Manufacturer, speed grade and package are not stated in the name, so check the document header. Datasheets like this list the pinout, supply voltage, data polling and write timing used by programmers. They help when reading firmware out of an older controller board or verifying a replacement. Confirm the exact marking and suffix printed on the chip, as different vendors and variants may differ in timing.
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 @cyberlanelectonik. 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.