There are broadly speaking three categories of redirect_uris for native applications

1) loopback URIs (http://127.0.0.1:2344/oauth2redirect, currently supported by qtnetworkauth via QOAuthHttpServerReplyHandler)
2) private uri-schemes (com.myapp.com:/oauth2redirect)
3) claimed "https" scheme URIs (https://my.app.com/oauth2redirect, what this Jira task is about)

This task is about 3) and specifically about Android "App links" and iOS/macOS "Universal links" which are platform-specific implementations of it. They are safer and end-user-friendly redirect mechanisms.

This most probably means implementing a new ReplyHandler class into qtnetworkauth module (QOAuthUriSchemeReplyHandler).
Also documentation must include what the application developers need to do with regards to application manifests (Android) and entitlements (iOS).
This task relates closely to adding support for "private URI scheme redirection". This task and that task will in all likelihood share the same convenience class.

Automatic CI testing is likely going to be somewhat limited as the custom URIs may invoke a dialogue for the user to select an application.
Furthermore the use of claimed HTTPS requires setting up assetlinks file (Android) or AASA file (iOS) on a hosted HTTPS capable server.