It is based off of OWGR.
They take 60 total golfers.
Top 15 in the OWGR qualify but no more than 4 per country.
This means USA cannot bring Patrick Cantlay, Bryson Dechambeau, Brian Harman, Sahith Theegala, and Max Homa.
After the top 15 then they go down the list but no more than two golfers per country.
The first non-USA player left out is #23 Tyrell Hatton of England.

This means another 21 of the top 60 golfers who are USA golfers are left off the list, but:
#261 Gaganjeet Bhullar of India will play,
#263 Ben Campbell of New Zealand makes it in,
#269 Nicolas Eschavarria of Columbia does too, as well as
#281 Kristoffer Ventura of Norway,
#287 Phachara Khongwatmai of Thailand, and
#312 Abraham Ancer of Mexico