Saved on this device only. System follows your phone or computer's setting.
Print a QR sticker for each item or a whole location's contents. Set the base URL above first so scans open the right address. Scan reads QR labels and product barcodes or ISBNs; the camera only works over HTTPS (see the README's “HTTPS and camera scanning”), and a barcode fills the form only while Lookup is on.
The .zip backup contains everything, including photos and files — keep a copy off the server.