What are the "Other" emails in the Mail Flow Summary report ?

[flpl]

Good afternoon,

What are the "Other" emails in the Mail Flow Summary report ? 

I can't find a section about this in the documentation.

Here is a screenshot to illustrate

Thanks in advance,

[SriramV · Accepted solution]

Messages which are classified, but not threatening

like Graymail. Bulk, Social Networking and Marketing Messages