From reviewing the license, the portions under the ee directory are not open source, they’re source-available with some additional grants of rights given certain conditions.
Here’s the definition I use for “open source”, and here’s the one I use for “free software”. Most (all?) free software licenses meet the definition of free software, but not all open source licenses meet the definition of free software, so that’s why I tend to set that free software is a subset of open source software.