Wireless section schematic for the Samsung SM-A21s, covering WiFi, Bluetooth and GPS, in a 3.82 MB PDF. It documents the connectivity circuitry, typically the wireless chip area, its supply rails, antenna paths and matching components. Technicians use it when WiFi will not turn on, Bluetooth has poor range or GPS cannot get a fix, checking rails, antenna feed parts and test points. Open it with any PDF reader, and confirm the board is from an SM-A21s before relying on the component positions shown.
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 @phoneSchematics. 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.