This is a personal time tracking app designed and developed by and for myself. More info at my blog and Hacker News.
You're welcome to try it out for yourself by installing an APK from the releases page, but be warned that the app requires Android 8.0+ and has undergone essentially zero QA! Please open a PR or issue if you're having problems.
All data is saved to a Sync/chronofile.tsv file in your device's local storage - nothing ever gets sent over the internet.
I used this project to learn Kotlin and (re)learn Android development before I began work on the Duolingo app, which is now 100% Kotlin!