This simple plugin is based on The Pomodoro Technique, which is is a popular time management method.
Pomodoro Chrome Extension gives you a simple user-friendly timer interface to utilize the pomodoro method.
Here is how to use it:
1. Click on the browser action icon.
2. Select number of minutes for the deep work session.
3. Work for the selected number of minutes :)
The extension does not require registration, it requires minimal permissions, and does not store your data.
It's open source: