This directory is intentionally empty.
By default, NTF uses this directory to search for test cases and configuration files, which is handy when we use NTF directly from the sources.
The default organization under this directory is as follows:
external/nuttx-testing – for test cases
external/config.yaml – for the YAML configuration file
external/nuttx – for the NuttX kernel source code
external/nuttx-apps – for the NuttX apps source code
Each default path can be overridden from the command line with the appropriate option.