How can I use saved data from a form in a page template?

I have a frontend form for recording hours spent on a project. It saves the data nicely in the user/data folder. How can I iterate over that data in a TWIG template so that I can build a page that shows who spent time on what projects?

A plugin needs to make that data available to twig. Look at how Comments plugin works, for example, it's a very similar concept.