There's a "bug" on this page:

https://knative.dev/docs/getting-started/quickstart-install/

kn quickstart kind will fail because registry is not created by default anymore.

Documentation fix:

kn quickstart kind --registry.

Looks like there's a whole process to contribute to docs, otherwise I would have just done that instead of filling a bug :)