I’m sure there are International students accepted to Harvard that have received “full aid” and they can respond accordingly. However, international students need to understand what “full aid” means. Yale has a bit more information on their website than I could find at Harvard: https://finaid.yale.edu/costs-affordability/costs/international-students-and-us-taxes
What that means is an international student on “full financial aid” receiving scholarships for tuition, room, board, personal expenses and travel MUST file a US tax return and pay taxes on the amount that exceeds tuition. In Harvard’s case, that would be: https://college.harvard.edu/financial-aid/how-aid-works/cost-attendance
$10,927 = Room
$ 6,755 = Board
$ 3,000 = Travel
$ 4,000 = Personal
$24,682 = Total X .14 = $3,455
So, an international student on “full financial aid” must take out a loan (or have their parents pay) $3,500 to $4,000 per year, or about $14,000 to $16,000 over the course of four years to attend Harvard. “Full aid” is not really free, even at Harvard.