This is a chrome extension that notifies you when ChatGPT is done generating a response while you are doing other stuff.
To install the extension from source, you need to clone the repository and load the extension into your browser.
In chrome open the extensions page by typing
chrome://extensions
in the address bar.
Then enable the developer mode in the top right corner and click Load unpacked
.
Then select the folder of the cloned repository and the extension should be loaded.