A 308 KB PDF on the 24C164 serial EEPROM, a 16 Kbit I2C device that, unlike the plain 24C16, uses its address pins for cascading several chips on one bus. The trailing p in the name probably marks a package variant, which the name alone cannot confirm. Expect pinout, addressing, write timing and electrical data. Technicians consult it to tell the 24C164 from a 24C16, since the addressing differs, and to set the right type in programmer software. Back up the existing data before writing.
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.