Compared to other booking sites, Airbnb has made it extraordinarily easy to report one's earnings - gross (earned) income, as well as the service fees paid to ABB, and also Occupancy Taxes paid if they are collecting and remitting on your behalf (the last two are already deducted from the gross earnings - I checked carefully and did the math multiple times to be sure).
I, for one, am most grateful for this. It all can be found under 'Transaction History', then 'Gross Earnings' (to the right of 'Future Transactions'). Easy as pie. The other booking site I am on made it a virtual nightmare to try and get this information.
The reporting requirement is set by the IRS, not Airbnb.