Only the number 29010 names this 727 KB PDF, listed as a schematic; the pattern most likely corresponds to a datasheet for a 1 Mbit 29-series parallel flash memory, with vendor and package not stated. It is useful for checking pinout, sector arrangement, device ID and the program or erase command sequence before reading or reflashing an old BIOS or firmware chip. Its size matches 29010a, so compare both. Back up the original contents with a programmer and verify the chip marking first.
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.