NXP document UM10391, a user manual in PDF form catalogued here as a schematic reference. The name gives no further detail on the part covered, so open it to confirm which NXP device it describes. User manuals of this type explain the internal blocks, registers, pin functions and peripheral configuration of a chip, which helps when tracing signals to the IC, identifying pins to probe, or checking how the part should behave on a board. Match the exact chip marking before use.
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.