Google's John Mueller was asked about premium indexing on Twitter and he responded "There's no "premium" indexing on Google's side."

Part of that question was also around building backlinks, so it sounded in general a bit spammy. Here is the back and forth:

Both of those sound like spam, to be honest. There's no "premium" indexing on Google's side, and manually building backlinks sounds like link-dropping. — 🍌 John 🍌 (@JohnMu) March 1, 2020

The only thing that I can think of as "premium" indexing would maybe be the indexing API but that is only for job postings and live streams. They are also short lived types of content.

So I am not sure where a rumor like this came from?

Forum discussion at Twitter.