Hi,
The Education version has Dansguardian installed (not configured, I would not know how to do that and don't have spare time to learn now anyway), but for Firefox no extension installed.
Here is a list of extensions you might want to look at. Please tell me if you notice one that might be ok for a version meant to be proposed as a community release : ease to use, a license allowing redistribution, and performing.
Thanks,
Mélodie