No information on the developer's web site and precious little information in the App Store. My most important question before I spend time (and money?) on this is: Does the app actually write to the material being shown, or is it a true overlay? Presentation software (like Zoom) actually modify the presentation, which is something I do NOT want to do. It would be nice to be able to point to something on screen in real time. If this can do that without writing or modifying stuff, I'm in!