Datasheet named RTM876-660, a 246 KB PDF. RTM-prefixed numbers are typically Realtek parts, and this one is listed under the 660 variant, but the device function is not stated in the name and should be confirmed from the document title. Datasheets like this provide pin descriptions, operating conditions and application diagrams. Technicians use them to check supply pins, clock or control signals and to compare the marking on the fitted chip with the variant described before replacing it.
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 @ic_mosfet_pdf_datasheets. 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.