Oplm file

See if this helps: https://support.pocketcasts.com/article/im-new-to-pocket-casts-how-do-i-import-my-opml-2/

Sadly it doesn't. In fact the entry for Apple podcasts is actually for a different podcast app. Woindering if anyone has solved this problem yet?

From comments I've seen you may be able to do it on iTunes (Windows, or older Macs) but not on the Podcasts App.

Import Stitcher OPML file to Apple Podcast - Apple Community