The dev server allows you to develop components locally, and test them in the Click editor, without having to publish your packages.
From your component repo, run:
npx click dev
Then from the editor, reload the page, and look under the "Add Layer" menu. You should see your local components available to add to your project.
Note: if you want to use a different dev-server than the default one, set CLICK_DEV_SERVER=https://...