I built Kanbanero because I wanted a kanban app without an account or server and with data in a format I could easily read.
Each board is a plain JSON file in a folder you pick, so you can back it up with Git and edit it in your text editor.
It's a macOS app. Built with Flutter. keyboard-driven, light and dark themes.
$8.99 one-time on the Mac App Store. No subscription, no IAP or ads.
Happy to answer any questions.