Create a "File Handler" for user defined SafeSecrets file type.

[glenw921]

It is important that SafeSecrets not have a pre-defined file type that would let anyone with access to a file know what software use used to open the file. Let users specify their own file extension/type and then register that file extension with a PWA File Handler. This way when a user taps/clicks on one of their SafeSecrets files it will automatically open the SafeSecrets app, but only on the one device where the user accesses SafeSecrets files.

[glenw921]

File handlers must be registered in the PWA manifest, which is not updatable after publication. The only way to implement this feature is to have a utility create a custom publication of SafeSecrets for each user on their own device. A local webserver would be required for HTTPS context, if the code requires HTTPS context. :|