Chromium 90 introduced a new way of navigating to schemeless URLs: It first tries HTTPS and only falls back to HTTP if that is unavailable: Chromium Blog: A safer default for navigation: HTTPS.

Unfortunately, I can't see a way to use this from QtWebEngine: It needs a QUrl, and QUrl.fromUserInput("qt.io") results in http://qt.io (which is probably okay in the context of a generic QUrl).

I tried url.setScheme("") and thus loading //qt.io, but that simply results in about:blank being loaded.

I suppose either that should work, or perhaps QWebEngineView/Page::load() or QWebEngineHttpRequest could have a way to pass an user input as string, which is then handled according to Chromium's rules.