As per title, I could not find any remove or delete button to remove created custom app.
Hello @mblaw , Please login into Shopify partner dashboard → Open Apps → All apps → Open the app which you want to delete → Open configuration and scrolled down, there you find a delete app button for that particular app.
Feel free to reach out if you have any questions or need assistance.
Best Regards,
DWS.
Is it possible that the Apps entry does not exists anymore and this answer needs to be updated?