What a lovely designed app! Oh wait, somehow this looks familiar. Would have been nice if they have asked before publishing my app on which I have the sole copyright on. https://apps.apple.com/de/app/instacastplus/id6472283494?l=en-GB
‎InstacastPlus

‎InstacastPlus is built on the previously popular podcast app Instacast. Discover podcasts that entertain, inform, and inspire. Features: • Browse hundreds of curated collections. • Follow and save your favorite shows to your library. • Use playback controls to build and manage your queue, control…

App Store

@martin but wasn’t that the idea when you open-sourced the app under the GPL?

https://github.com/martinhering/instacast/

GitHub - martinhering/instacast: Instacast Core is a podcast player for iOS.

Instacast Core is a podcast player for iOS. Contribute to martinhering/instacast development by creating an account on GitHub.

GitHub
@salocin Open Source does not mean you can claim copyright and publish it.
@martin specifically the GPL means they can publish it, provided they provide the source code of the changes they (presumably) made.