Just in case anyone wants them, I've got MD-PhD only prompts for (from 2019-2020 cycle): Baylor, Georgetown, University of Florida, University of Kansas, University of Maryland, University of Minnesota, University of Rochester, University of Texas Medical Branch, and Virginia Commonwealth. Feel free to PM me!
This is one question asked in UW's MSTP supplemental application, which you have to submit to be considered for a secondary. They also give you space on the supplemental to supplement your AMCAS Personal Comments, describe on your research interests, and elaborate on all of your research and clinical experiences. You don't need an invitation to complete the supplemental and it's available on their website.
Last year's secondary included questions about your preparation to become a physician, a short autobiography, a diversity question, an adversity question, and a question about the effect of inequities on patient you've worked with.