Do you need to manage your work time with Pomodoro technique? Do you use GNOME Shell? Then GNOME Pomodoro by Kamil Prusko is the right utility program for you. Once installed, GNOME Pomodoro will act like an extension and be placed on the top panel so you can control it from GNOME Tweak Tool.
GNOME Pomodoro is not merely a Shell extension. So it is different with the normal extension like EasyScreenCast. Fortunately, you can install GNOME Pomodoro from official Ubuntu repository (universe) for Ubuntu versions 15.10 (wily), 16.04 (xenial), and 16.10 (yakkety). To install it, type this command:
sudo apt-get install gnome-shell-pomodoro
For older versions of Ubuntu, you may follow installation instructions from GNOME Pomodoro official website http://gnomepomodoro.org.
Once installed, GNOME Pomodoro will stay on the top panel just like some other Shell extensions.
First, you must set your timing up to use in Pomodoro. Find Pomodoro on the top panel > click it > click Preferences > set the time values as you wish. For example, my Preferences picture below showing: I need 10 minutes working (Pomodoro), 1 minute primary break (short), 2 minutes secondary break (long), and I have 4 Pomodoros until the secondary break. These are the minimum setup you should have.
To start Pomodoro timing, click on GNOME Pomodoro icon on the top panel > Pomodoro Timer > switch it ON. A new notification appears asking you to focus. It's your time to work.
Every time your Pomodoro period is over, a notification will be shown asking you to break for certain short period of time. When your Pomodoro circles are over, then the notification will be shown again asking you to have break for long period of time. GNOME Pomodoro will block the screen while showing a countdown timer for your break time.
You may disable or enable the Pomodoro icon on the top panel by controlling it from GNOME Tweak Tool. See the Extensions tab on the Pomodoro entry.