A 163 KB PDF catalogued as a schematic, though the name points to the 28LV256, a 256 Kbit low-voltage parallel EEPROM, so it is most likely a datasheet. Parallel parts like this have separate address and data buses plus chip enable, output enable and write enable pins, all of which the document should map out. Use it to confirm the package pinout and programmer settings before reading or writing the chip, and check the exact manufacturer marking on the part, as several vendors made this number.
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.