PDF sheet named BQ24728, a Texas Instruments notebook charge controller part number, at 94.3 KB. Given its small size it is likely a brief datasheet or excerpt rather than a complete manual. It is still useful to find the pinout, see the reference application circuit and know which pins carry adapter detection, current sense and gate drive. Technicians compare measured voltages against it while troubleshooting charging or power-path faults on laptops, after confirming the chip marking matches this part.
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 @laptopbios21. 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.