The extension is a visualization of the 30-second rule, which is a restriction on forum users in Hattrick to post only once every 30 seconds.

It is similar to the "Last post from X time ago" rule on Twitter, where the posts are removed when the time is up.

You can add the extension to your app as follows:

1. Go to the Extensions tab of your app settings.

2. Click "Add new."

3. Click "Create a New Theme."

4. Fill in the values for the colors.

5. Click "Start."

The extension will show up in the list of themes you have created.

You will see a "Last post from X time ago" widget for each theme.

The widget will be removed when the time is up.