ArduPilot communication libraries (GCS_MAVLink, AP_SerialManager, MAVLink routing,
telemetry protocols). Use when:
(1) Working on GCS_MAVLink or MAVLink message handling
(2) Adding new MAVLink messages or MAV_CMD commands
(3) Configuring serial ports or streaming rates
(4) Implementing parameter, mission, or fence protocols
(5) Working with FrSky, CRSF, MSP, or other telemetry
(6) Setting up network communication (TCP/UDP MAVLink)
(7) Debugging communication or routing issues