Organizations or users can restrict the visibility of repositories owned by them. This will most likely detach and move into the new network and some of the features will be unavailable once the repository is private.

To change repository visibility from public to private:

  1. Login to GitHub.com and navigate to the repository landing page.
  2. Click on Settings.
  1. Scroll down and locate “Danger Zone”.
  1. Click on “change to private”. It will prompt to change in the visibility of the repository.
  1. Continue with the prompt. This will alert the window with “click on read and understand effects”.  This will impact stars and watchers, code scanning, fork, etc.
  1. Click on “Make this repository private”. 
  2. You can see the lock icon with “private” next to the repository name on the landing page of the repository. 

Reference: Setting repository visibility