This is a simple example demonstrating a more complex package using l3build.
Here, the code files are located in a code/ subdirectory, and documentation files in doc/.
In this simple case, the code and documentation consist of only one file each, which hardly seems necessary to subdivide.
But as a package becomes larger it makes more sense to break the .dtx file into independent parts of the code, and the documentation can be broken itself into parts and chapters.
This is left as an exercise to the energetic package writer studying these examples.
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