Short PDF schematic of about 72 KB whose name points to the X63C project and an SD daughterboard, likely the card reader board; no laptop model or revision is stated. X63C is a Quanta project code, and elsewhere in this set it appears for the HP ProBook 450 G3. A compact sheet like this is handy for tracing card-reader power, detect and data lines and the connector pinout back to the main board. Verify the daughterboard part number printed on the PCB before using it for diagnosis.
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 @LaptopsBoardview. 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.