Gary Wilson has written up a post detailing the cyclomatic complexity of Django (the Python web dev framework).
Wikipedia defines cyclomatic complexity as:
Cyclomatic complexity is a software metric (measurement) in computational complexity theory. It was developed by Thomas McCabe and is used to measure the complexity of a program. It directly measures the number of linearly independent paths through a program's source code. The concept, although not the method, is somewhat similar to that of general text complexity measured by the Flesch-Kincaid Readability Test. Cyclomatic complexity is computed using a graph that describes the control flow of the program. The nodes of the graph correspond to the commands of a program. A directed edge connects two nodes if the second command might be executed immediately after the first command.
It isn't often that you see software engineering metrics applied to open source projects. I wonder why that is?