I guess it's really safe cause it's open source, you can make notes on your habits but don't really do that. Its simple. Really fast. Haven't found a way to connect it to notion. In general it's a great app to track you habits. Does its job. Not more, not less.
Habitica - Habitica is a free habit building and productivity application.
Sass - Syntatically Awesome Style Sheets
HabitBull - HabitBull
PostCSS - Increase code readability. Add vendor prefixes to CSS rules using values from Can I Use. Autoprefixer will use the data based on current browser popularity and property support to apply prefixes for you.
Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Stylus - EXPRESSIVE, DYNAMIC, ROBUST CSS