Caffeine is a little daemon that sits in your systray, and prevents the screensaver from showing up, or the system from going to sleep. It does so when an application is fullscreened (eg: youtube), or when you click on the systray icon (which you can do, when, eg: reading). This is a fork of Caffeine 2.4, since later versions dropped support for the systray icon in favour of automatic detection of fullscreen apps only. The dependencies require python3 support where available and python3 should be installed before any of the other dependencies. setuptools-scm is only required as a build dependency and can be skipped if you would rather have it automatically grabbed from pypi.python.org during the build process.