The learnlatex.org site is aimed at providing a basic introduction to LaTeX. To make the material accessible, it is broken down into a series of small lessons. The demonstration files provided are also hosted on-line to let new users get started straight away.
The LaTeX ecosystem is rich and complex, and this can be intimidating to new users. To avoid overload, this site therefore is quite deliberately limited in scope, covering essential ideas using core LaTeX packages and classes, and leaving further help to other places.
The content of the site is available under the Creative Commons BY-SA 4.0 license. That means you can use the material as long as you say where it came from and let others do the same.
The code examples are licensed as CC0. This is a legal text that is (essentially) the same as Public Domain, at least in countries where that concept exists. The key point is that you can use the examples without any issues. You do not need to reference them, you do not need to share them when you modify them: you can just use them.
Recent Changes are listed in the Change Log.
2, Dowthorpe End