I haven't done the numbers in a while but from the given ratio I would assume your line checker tool treats docstrings as code. The red part there is for the most part just documentation, not code: https://github.com/mitsuhiko/flask/blob/master/flask/app.py (as an example)
Counting Flask v0.8 with cloc yields twice that:
And that doesn't include the size of Werkzeug, without which Flask cannot run: Including the contrib and debug packages of Werkzeug adds another 3000 LOC.