Are you searching on the Odroid proper or inside the docker container? If you are running HA in a container then you have to enter the container to look at the code. Your configuration files, depending on how you set it up, will be outside your container.
Really you want to clone the integration into /config/custom_components, for example, if you’re adding debugging to the demo integration you’d clone the relevant branch found from the source link (eg the master branch to /config/custom_components/demo.
Make your changes there, and restart HA to load them.