"Inspired by the great book Getting Things Done by David Allan. This is a program I wrote because I badly needed it in order to organize my own time. I failed to find anything, on any platform, that satisfied my requirements:

Free
Preferably Open Source
Designed after the principles in "Getting Things Done"
Safe; no unnecessary app privileges, no enforced integration with Google (or any other) services in order to work.
Fast and efficient to work with
Safeguards against losing data by accidents