Only the number 271001 appears in this 134 KB PDF name, and it is listed as a schematic, though the pattern suggests a 27C1001-style 1 Mbit EPROM datasheet rather than a circuit diagram. The vendor, speed grade and package are not stated. Such a sheet is used to look up pin assignments, the programming voltage and erase requirements when dumping or reprogramming an old firmware chip. Confirm the chip marking before selecting a programmer profile, and always keep a verified backup of the original image.
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.