Written for the colleague who has to put it in writing. Every claim here is also in the app itself, under its ? button — the app's copy is always true of the exact version you're running.
On your computer, in one file: Documents/Sage Stage/sage-stage.json (the desktop app keeps two weeks of daily backups beside it, and can show you the file). Undo history and snapshots live in the app's own local database, also on your computer. In the browser version, everything lives in that browser's storage instead.
There are no accounts, no server of ours, and no analytics — nothing about you or your class is collected, and there is nothing to hack at our end because there is no “our end”. Even the typefaces ship inside the app.
Three things use the internet, all chosen by you: wallpaper photos if you pick one, template sources your school adds, and web content you put in the Video or Embed widgets. Your class data rides on none of them. These help pages are a normal website visit, opened only when you click.
Class lists stay on the device and reach no one. Printed sheets are designed to carry no child's name, so a sheet in a book bag discloses nothing about another child. School policy on names still applies to what you type — first names are plenty.
The Webcam widget shows the camera live (a visualiser); the Noise meter listens only to measure loudness. Nothing is recorded, kept, or sent — when the widget closes, the camera and microphone are released. The operating system asks your permission the first time, in its own words.
Export everything produces one JSON file you own — that's portability. Erase all local data deletes everything on the device including backups and snapshot history, and says so before it does it. Deleting the data file in Documents amounts to the same thing.
“Sage Stage is local software. It has no accounts, no cloud storage, no analytics, and no data sharing; personal data never leaves the school-controlled device, so the school remains data controller and no processor relationship exists. Erasure is the in-app Erase button or deletion of the data file (Documents/Sage Stage). Camera and microphone, where used, display or measure live and record nothing.”