Podcasts is an UWP application that you can find here: https://www.microsoft.com/store/apps/9nblggh1zj3r
Feel free to send PR or open issues. But as this is a side project, I cannot guarantee fast response time.
Podcasts was not intially meant to be OSS so you may find code which could be weird or fun :) Furthermore the first version of Podcasts was done for 2 processes background audio. Then it was moved to a single process background audio.