Hi folks! Learning Equality co-founder (and that “former KA intern”) popping in. 
Thanks for hosting these great discussions!
First thing I wanted to clarify is that the majority of the Khan Academy videos are still CC-licensed – in particular, the vast majority are CC-BY-NC-SA. The exceptions to this are for content that came from KA partners (e.g. MoMA) or co-created with partners. It’s more hidden than it used to be, but if you look on a video page on the KA site, way at the bottom below the comment section, you can see text like “Creative Commons Attribution/Non-Commercial/Share-Alike” (e.g. here).
That said, there are a few things that have always been a bit muddy:
- The KA exercises don’t explicitly specify their licensing on the site, as of 2014. We have verbal clarification from them that the intention is for them to still be open, with the same caveats as the videos (certain partner-provided content, e.g. College Board). The rule of thumb being “if a video is CC, then the exercises alongside it are also CC”. We pushed to have this made more explicit, but it looks like it’s been left implicit so far.
- Their licensing metadata on YouTube hasn’t always been accurate. We pushed for some cleanup and it got better. I believe we primarily refer to API results to determine licensing, when bringing content into Kolibri, as it’s more canonical.
- I too find their Terms of Service at times confusing, and in some cases possibly contradicting itself. The “Downloadable Content” pieces referenced above I think are largely (in terms of intentions) targeting their mobile applications. Section 7.2 first sets up a generic “personal, non-commercial” license as the default for “Licensed Educational Content”, and then 7.2(a) specifies that some content is made available under an “Alternate License” (with the example of CC being given). Despite this being phrased here as the “exception”, it’s actually the case for the majority of their videos.
- One shift that has definitively happened over time is a move away from open-source, on the code side. When I interned at KA in 2012, the full KA website codebase was available for download, with many components (e.g. khan-exercises) released as explicitly open-source components. Later that year or in 2013, that download was removed, but some elements stayed open-source (and these were the pieces we incorporated into KA Lite and Kolibri). In 2018, they archived the Perseus exercise renderer codebase (GitHub - Khan/perseus: Perseus is Khan Academy's new exercise question editor and renderer.), which is required in order to render their exercises, and moved it into their internal repositories for ongoing development. So far we haven’t had issues using the 2018 version of the exercise renderer, but issues may arise as it continues to diverge.
Hope that provided some useful context and background! In terms of Learning Equality’s approaches to licensing, we always advocate for as open a license as possible. And in KA’s case we’re operating under the explicit CC license. In some cases, however, we do negotiate “special permissions” for distribution through Kolibri from a content provider that is not otherwise fully open.