Place your NEDs inside this directory in the *signed.bin file format, for example ncs-6.2.3-cisco-ios-6.106.5.signed.bin.
The setup_add_neds.sh script automatically unpacks and adds the NEDs to the Docker image.
If you are using these NEDs for your own package, don't forget to update the Makefile of your package. See, for example, the Makefile of the router package.