What is the name of the DLC for Portal 2 that adds community-created puzzles?

What is the name of the Portal 2 DLC that adds community-created puzzles? It is called the Perpetual Testing Initiative.

The Perpetual Testing Initiative was a free title update for the Windows and Mac versions of Portal 2, released on May 8, 2012. Its main feature was an accessible level editor that let players build their own test chambers without needing to construct maps with Valve’s more complicated development tools.

The update also connected Portal 2 to the Steam Workshop, allowing players to publish, discover, download, and share community-created puzzles. This turned the game’s carefully authored puzzle system into a much larger platform for player experimentation.

Puzzle Maker and Community Test Chambers describe features or concepts associated with the update, but they are not its official title. The Lab is a separate Valve game made for virtual reality, not the Portal 2 downloadable-content update. Portal 2 also received other additional content, including the cooperative campaign Peer Review, which is why the names of its expansions can sometimes be confused.