These event type which I search the definition for quite a while, I do not find any comments about its.
So listing the Event type below, hope someone can help me to explain its meanings.
By the way,my customers say these logs are related to WAF, but I am not sure if this information is helpful.
At the last, show a partial log content for you, hope you can better understand the situation.
Go to Settings->Event types and look up the definition of each eventtype in your list. That will show what data matches each event type.