Which class does the method libraryResource() come from???

[TInaTinaTian L]

I know that Jenkinsfile pipeline DSL can resolve libraryResource() magically without explicitly providing any context (pardon my poor understanding of the pipeline DSL).

But if I want to use libraryResource() as a regular groovy class, how do I use it???

Is it a static method? Which class does it come from? Which package do I import?