QtQR is an application (or website) that enables users to easily generate, scan, and store QR codes. It allows users to quickly create QR codes to store and share links, contacts, messages, and other types of data. QR codes can be scanned with a camera or smartphone and the data can be read and understood. QtQR also allows users to save and store their QR codes for future access and use. In addition, users can also customize their QR codes with logos, images, and other features. QtQR is a great tool for businesses and individuals who need to quickly share information, contacts, and other data.
Discontinued is not compatible with newer versions of Firefox, etc.: https://addons.mozilla.org/en-US/firefox/addon/OfflineQR/