Filed among schematics, this 91.7 KB PDF is named 2764 with nothing else to identify brand or board. The number corresponds to a classic 27-series EPROM designation, although the document should be opened to confirm its subject. Such sheets typically include the pin diagram, mode table, programming procedure and access times. They are handy when reading a firmware chip from older hardware with a universal programmer; compare the manufacturer prefix and speed marking on the part with the document before proceeding.
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.