It would be really useful to be able to link to a flow starting point as a prototype interaction, especially if it could be done across different pages in a prototype. For example, it would be a quick way to add a “restart prototype” button without having to hunt through a list of frames, or to create a launch screen for a bunch of prototypes.
Right now you can use the share link to the prototype, but it’s a pretty clunky way to do it.