Good questions

It lives in your menu bar and plays a mechanical keyboard sound every time you press a key, in any app.

No. A key press is used to choose which sound to play and is then forgotten. Nothing you type is saved, and the stats keep only totals.

No. Clicka has no network access: no accounts, no analytics, no syncing.

That is how macOS lets an app notice key presses in other apps. Clicka only listens. Without it, there is nothing to play a sound for.

macOS hides key presses in secure fields from every app. That is expected, and it is a good thing.

Yes. Put a sound pack folder in Clicka's sounds folder, press Reload in Settings, and pick it from the list. Settings has an Open Folder button that takes you there.

Press ⌃⌥K from any app, or flip the switch at the top of the menu bar panel. You can record a different shortcut in Settings.

Any Mac running macOS 13 Ventura or later.

It isn't out yet. This page will link to the download when it is.

Turn off Launch at login in Settings, choose Quit Clicka from its menu bar panel, then delete the app.