This file describes the subdirectories contained in this directory. defender : Contains a Git sub-module of the AWS IoT Device Defender client library. ota : Contains a Git sub-module of the AWS IoT OTA client library. ota-pal : Contains implementations of the AWS IoT OTA client platform abstraction layers - one per subdirectory. shadow : Contains a Git sub-module of the AWS IoT Device Shadow client library. tools : Contains tools that automate setup and provisioning actions.