Reference PDF, 181 KB, for the KA2923, an IC from the KA prefix series; the name contains only the part number and does not state its function, so that must be read from the document. It is classified as a schematic but most likely provides the pinout, block diagram and application circuit of the chip. Technicians use files like this to identify supply and signal pins, compare measured voltages with expected values and judge whether the component is faulty. Match the full marking on the IC before ordering any replacement.
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.