Code blocks with links have a different style on the website. For example, on the Installation page:

• The npm install -g corepack command is in a white box with a copy button.
• The yarn init -2 command is in a black box without a copy button.

There is also the Editor SDKs page.

I think the link is added for yarn actions, which is why the code block layout isn't applied. If the language is specified in the code block: the link isn't added and the layout is applied.