Replace Epiphany web apps with Progressive Web Apps
Looking at what other platforms are doing, it seems possible implement local installation of web apps in a more sophisticated manner than we're currently doing in GNOME. For example, nowadays it's possible to pull in an app icon from the website itself. Many "progressive web apps" also have offline capabilities.
This would be a major enhancement to our existing web app capabilities, and would allow them to serve as more capable replacements for native applications.
Perhaps @mcatanzaro can fill us in on what's missing from a platform perspective.