This is a core block and thus available by default in Gutenberg WordPress editor. No download required.
The WordPress Preformatted Block in Gutenberg allows you to write text and keep all spaces, line-break intact. Basically, this Block displays the text exactly as you type. This block is similar to the text and code block.
Preformatted Block Features
The Preformatted block toolbar has basic formatting options. As this is a simpler text block it does not has any additional options in the sidebar panel.
This is how it looks on the frontend.
The preformatted block added in the editor.
Preformatted block's setting panel.