`ContextActivities` --> `contextActivities` at https://github.com/adlnet/MasterObjectModel/blob/288aa8537ae0e734f2726ce04bc9070f3acc2f4a/MOM_0_13_0.json#L921 per https://github.com/adlnet/xAPI-Spec/blob/master/xAPI-Data.md#246-context
ContextActivities-->contextActivitiesatMasterObjectModel/MOM_0_13_0.json
Line 921 in 288aa85
per
https://github.com/adlnet/xAPI-Spec/blob/master/xAPI-Data.md#246-context