What has happened to the libraries?

Hi,

I don't mean to ask a silly question, but have been reading the CI4 documentation. Was thinking about testing out CI4 on an old domain name. But then I realised that the libraries have gone.

I know they are just classes, but I have got into the habit of super thin controllers and models, with most of the work being done in libraries.

Are libraries now just models?

I am sorry if this is a silly question.

Paul.