PDF document for the TDA7491P, a 1.45 MB file that is most likely the component datasheet rather than a board schematic, judging by the part-number name. The TDA7491P is an STMicroelectronics class-D stereo audio amplifier IC. Its datasheet gives the pinout, typical application circuit and electrical limits, which help when checking supply voltages, standby and mute pins or output stages on a faulty audio board or TV. Compare the exact package marking on the chip with the document before substituting parts.
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 @pdf_servicemanual. 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.