Hi,
> how TestComplete knows which port the DevTools are running on...
It is my understanding that TestComplete has no idea about DevTools. It can connect to CEF page via CDP (which is a protocol), but cannot do something via DevTools.
> Isn't CEF-based all lumped into the same support?
No... Definitely not.
CEF support is well described in the https://support.smartbear.com/testcomplete/docs/app-testing/web/cef/about.html help article which I really recommend to carefully read for details.
A lot of depends on the version of TestComplete and the tested application - whether it is WPF-based or not and what version of CEF is used.
The fact that CEF page can be connected to via DevTools from remote regular web browser says nothing. Page can be connected to from DevTools, but I do not know whether it can be controlled from there (I mean, say, whether button can be kind of clicked from DevTools and how to wait for the click result).
Past week we lost CEF support for some application that I am assisting with test automation. The reason was because Development updated CEF to one of the latest version and the application itself is exactly WPF-based. And for this case only pretty old CEF version is supported as per referenced help article. So the current state with this application is pretty much like yours: CEF page can be connected to via DevTools from remote web browser but TestComplete cannot access CEF web page (the leaf object in the Object Browser is CEFBrowser itself) and I really not sure whether something can be done in the current situation.
