PDF document filed as a schematic for the ISL88731A, which the name identifies only by the part number; it is the Intersil SMBus-controlled battery charger IC found on many laptop boards. Material like this gives the pinout, reference circuit and typical component values, useful when diagnosing a board that will not charge or shows no adapter detection. Compare the reference design with the laptop schematic, check the sense resistors and input MOSFETs, and verify the exact marking on the chip before swapping 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 @ShareMan_Electronic_Files. 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.