Code that is used by others to access Open edX platform APIs is generally Apache.
The propagating nature of the AGPL makes it difficult for some people to adopt. For repositories where broad use is more important than shared improvements, the Open edX project generally uses the Apache license. This includes API libraries such as XBlock.
Broad-interest, or developer, tools are often Apache, too.
These are tools that may have nothing in particular to do with the Open edX platform and that do not run as part of the platform. They could be of interest to any Python developer, for example. Tools like this will often be Apache-licensed to enable their broader use and adoption. This includes tools such as bok choy.