Hmm.
One of those games says right in its description that it's a free fan game, another says it's a student project for educational purposes.
Two of these are prologues, full games in wishlist phase. A third is similar, but with an upcoming sequel.
One of them is free-to-play (rather than free-to-keep)

William and Sly: Classic Collection

Age of Advent

Divergence

Die in the Dungeon: Origins

Chronical

Beacon Patrol: First Horizons

It's a little bit confusing title, because it's not Steam that has made the games for Free. This is not a comparable situation to what Epic Games does. Steam has nothing to do with the offering, other than hosting the game on the platform. All games are made Free by their own publishers.

Also it includes games that are always Free in price, such as Age of Advent. It serves as a sort of demonstration of the full game. And it never had a price attached to it, if I see it correctly. This article is either AI generated or the author don't know what he is writing (sorry if you read this, but its my opinion). Please fact check stuff before posting.

steamdb is more useful for finding free promotions