Gumcast is a Gumroad RSS feed generator service. It lets you subscribe to Gumroad products as a podcast in Apple Podcasts and other podcast clients.
Gumcast is a webapp that lets you generate podcast RSS feeds for any product in your Gumroad library. You can use these feeds to "subscribe" to a Gumroad product in your favorite podcast app which provides many benefits:
tldr; Due to a Gumroad API limitation, this is the only way to access Gumroad library content through the API. Gumcast is working with Gumroad to improve this hopefully soon.