This is an example web browser built with Python and Qt. Using the QtWebEngineWidgets system introduced in Qt5.6, this provides a single-window browsing experience with the usual controls, as well as saving and loading HTML.
If you think this app is neat and want to learn more about PyQt in general, take a look at my free PyQt tutorials which cover everything you need to know to start building your own applications with PyQt.
Icons used in the application are by Yusuke Kamiyaman.