Programmatically get values of perspective properties from API

In 8.3, is there any API that can be used to get the values of a particular property inside a window for a specific session?

I.e. if a user is having some issue, is there any way for me to get ‘hey, what’s this dropdown or checkbox set to for them’ without binding it to a tag?

You could create a message handler. Have the message handler input be the property you want, and have it write it to the log, or do whatever else you want with the value..

Not provided, but presumably possible with WebDev and Ted's message handler advice. The critical part of the WebDev API would be some way to target the user's session and page and view (via parameters to the API).