What Was That!?

A quiet day-by-day timeline on your macOS desktop that doesn't get in the way of your work. One entry per day, to remember or plan what matters.

Inspired by the video Linear Calendar in Apple Notes from the New Perspectives channel.

Features

• Not a widget! Clicks pass through the app until you press opt+m.

• Customization. Set everything to your taste — date format, size, font, opacity and more.

• Feed, Range, Month or Week. Everyone sees time in their own way.

• A color for every day. Mood, vacation, weather — come up with your own meaning. Consecutive days of the same color merge into a stripe.

• Calendar. If you need it, turn on your Mac's calendars.

• If one line isn't enough, press shift+enter, cmd+enter or opt+enter and keep writing.

• If you really run out of room, press ↗ and create a note in Obsidian or Apple Notes.

• Always there. Starts at login by default; turn it off in Settings → General.

• No accounts, no servers. Everything is stored in plain JSON in your Documents folder. Export all your entries anytime.

  {
    "2026-03-10": { "text": "🚧 Started the bathroom renovation", "color": 2 },
    "2026-03-12": { "text": "⚠️ Plumber" }
  }
  

• You can put the file in iCloud Drive to sync between Macs.

Screenshot

Install

Requires macOS 15 Sequoia or later.

Homebrew:

brew install --cask lukyanetc/tap/what-was-that

Manually: download the .dmg from the latest release. The app isn't signed by Apple, so you need to allow the first launch manually: System Settings → Privacy & Security → Open Anyway. Step-by-step instructions are inside the .dmg. (Homebrew does this for you.)

Build from source

You'll need macOS 15+ and Xcode. Open d-cal.xcodeproj, select the MyApp scheme and run. App Sandbox is off: the app needs access to its data file in any folder, including iCloud Drive.

scripts/build-release.sh makes a release build: a universal app (Intel and Apple Silicon) without signing, output as .app, .zip and .dmg in dist/.

Tests: the MyAppTests target (Swift Testing). Build MyApp before running them.

Thanks

[100% vibe coding]

Thanks to the New Perspectives channel for the idea of a linear calendar. Thanks to present times, when even I could make my own app. Claude Code — ❤️

The bundled fonts JetBrains Mono, IBM Plex Mono, Fira Code and Geist Mono are distributed under the SIL Open Font License; license texts are in MyApp/Fonts.