This is an example of a library. You may see a list of other libraries used on Rosetta Code at Category:Solutions by Library.
Wren-debug is a module which provides rudimentary debugging support for the Wren programming language. It consists of static methods within a single class, Debug.
It is the thirty-ninth in a series of modules (listed on the language's main page) designed to assist with writing Rosetta Code tasks or Wren code for any other purpose.
To use it all you need to do is to copy the source code (in the talk page) to a text file called debug.wren and place this in the same directory as the importing script.
As there is a dependency on the Wren-check module, you also need to copy that (if it is not already present) to the same directory as described here.