Github Helper автор Varun Sridharan

Add repository size to their github homepage.The purpose is to add a repository's size to its GitHub summary band (next to the contributors or license) using the GitHub public API.

If you visit a private repository, the addon will ask for a Personal Access Token: you can create one in your GitHub settings, don't forget to check the "repo" scope!
If you do not get the prompt for a token, you can click on the size element added by the addon on any public repository.

⚠ This addon use the size as returned by the GitHub API and may be innacurate due to how GitHub stores git repositories! See here and here for more informations.