make open pwa visible to websites..

[frank-dspeed]

Platform-specific applications can already use operating system APIs to enumerate installed applications on the user's system. For example, applications on Windows can use the FindAppUriHandlersAsync API to enumerate URL handlers. If PWAs register as OS level URL handlers in Windows, their presence would be visible to other applications.

[frank-dspeed]

https://docs.google.com/spreadsheets/d/1de0ZYDOcafNXXwMcg4EZhT0346QM-QFvZfoD8ZffHeA/edit#gid=557099940