They're using a Payment in Lieu of Tax (PILOT) program [0]. I've been trying to understand why these programs exist for corporations but having trouble finding definitive answers. My hunch is that it's a marketing trick to help people stomach the tax breaks and go "oh, well at least they're building a school". Possible that it also allows for legal negotiation of terms like amount and payment schedule that can't be applied directly to property taxes.

[0] https://blog.aboutamazon.com/company-news/amazon-selects-new...