PDF of 99.2 KB titled 25C64-128 and stored with schematics, apparently covering 25-series SPI serial EEPROMs in 64 and 128 Kbit densities. No manufacturer, device or board is named. Repair technicians use this kind of datasheet to check the SPI pinout, supply voltage, write-protect and hold pins and the instruction set before dumping the chip. When programming, select the correct density in the software, read the original twice and keep the backup, since an image of the wrong size will not fit.
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.