The 223 KB PDF called 93lc46 refers to a small Microwire serial EEPROM and is likely the datasheet rather than a board schematic. Expect pin descriptions, organisation options, opcodes and AC timing tables. Small EEPROMs of this kind store configuration data on many boards, and recovering a device often means reading and rewriting them with a programmer. Open it in any PDF reader, set the correct organisation in the programmer software, and save the original contents before erasing.
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.