I am sick of over-complicated time trackers. I want something as simple as a single screen with overview for a whole day, but be able to see it with precision granularity.

I'd like to discovery crossplatform opportunities of Swift language and also learn some SwiftUI. OS X app is ready enough (I use it daily), hopefully I will implement Linux and Windows apps before I run out of luck.

Do not use SPM (no support for macOS app bundles), use xcodeproj instead. SPM is there for the SPM testing purposes

open timeline.xcodeproj

Data is stored in the ~/Library/Containers/ru.redetection.timeline/Data/Library/Application Support/ru.redetection.timeline/timeline.sqlite

SPM is a way to go.

swift build --product "Timeline-linux"
./.build/debug/Timeline-linux

At the moment app expects no remote X windows, only ones from local machine. Data is stored in the ~/.timeline/store.sqlite