L3rn development manager Lindell Alderman fills in some details in comments here. Most notably, that L3rn is built with Python and the Django web framework. This is a pretty big deal, because while it is surprising that a school district would write its own web 2.0 application, it is downright shocking that they'd actually use web 2.0 development best tools and practices, instead of bureaucratic Java, closed ASP.NET or ugly PHP. Django is specifically designed to encourage "clean, pragmatic design," so there is a pretty good chance that if they do open source their code, it won't be illegible, unmaintainable shit. Here's some random bonus Django advocacy that popped up today.
A little Googling points to an earlier Plone portal Lindell's team created. I don't think I'd heard of this; not sure how I managed to miss it.