Datasheet in PDF form, 235 KB, named 29C040X and indexed under schematics. The 29C040 code is used for 4 Mbit parallel flash memory, and the trailing X likely marks a family or variant designation; no maker, device or board is given. Expect pinout, sector size, timing and programming details needed to read or write the chip with a parallel programmer. Check the exact part marking and package before choosing a device profile, and always keep a backup of the original contents.
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.