It's about the ownership of a stream.

Let's say a user deleted their account, but they have a stream that they made.
If they delete it, who becomes owner in place of them? The moderators?
And what if there are no moderators to replace them? Does the stream just get deleted?
Answers will be appreciated, thank you.

Are you asking about a particular stream at all? Community and Global mods can take over streams that are abandoned if the owner is deleted, but since it’s a new feature, we’re still figuring out its limitations ourselves.

Makes sense. But what if an unlisted stream by a deleted user gets taken over by global moderators, only for them to find out that the user who was in charge has been doing shady things on the stream?

No, I was just curious after seeing how the family fell onto new ownership

Ah yes. In the case of Imgflip family, Borderline deleted her account when she was the only mod so the stream was completely abandoned.

i need you to take over Femboy_furries_sream and give me owner please

If no owner does mod actions for 60 days, an active mod can claim the stream

The global mods take over.
It happened to tumblr posts, imgflip family, and greenpolitics. But now I own the tumblr posts stream instead

Oh okay

But what if there's a moderator?

the moderator takes over when Usufucci deleted his account the debate stream got handed over too me becuase I was the first person he made mod

Oh I see, thanks, Mav

I don't know what will happen if there are no moderators for the stream, but if there are moderators, then the first moderator recruited obtains ownership of the stream.
That has happened to me with the Dead_memes_stream a while back. I was the first moderator to be recruited. When the owner deleted his account, I became the new owner.