I've set discoverable to false ("discoverable: false" in the header) before saving this as "draft". Let's see if it remains.
No, it did not. (Now I think this has to do with the D" having been capitalized.).
Now I'm setting it again before publishing. Hopefully you won't see this in the Discover feed.
You didn't, THAT'S GREAT! To not hit the Discover feed with a post. put
discoverable: false
in the header of the post.
😀