There are 3 repositories under arduplane topic.
APM Planner Ground Control Station (Qt)
Howto use BeagleBone Blue with ArduPilot
Examples for the Library for Aircraft Dynamics And Control
Universal PCB for interfacing with CAN bus
Easy run multiple vehicles with Ardupilot SITL.
Program for lightweight fixed wing UAV for Teknofest International UAV Competition 2021 by Rasendriya AUAV UI. Automatizing target detection and payload dropping
Arduplane Firmware for HITL (Hardware in the loop) simulation using XPlane 10 and APM