B !full! Full Schematic: Raspberry Pi 4 Model

In the first hardware revision (Rev 1.1), the schematic shows that the USB-C port's two pins share a single 5.1K ohm resistor (Rd) to ground, rather than each having its own dedicated resistor.

Nevertheless, the reduced schematics are extremely useful. They contain enough information to understand the board’s architecture, build compatible HATs (Hardware Attached on Top), diagnose many power or I/O problems, and even derive some of the missing details through reverse engineering and community collaboration. Raspberry Pi 4 Model B Full Schematic