Sites are tracked by cultural ministries using restricted site inventories that are only open to government officials and established researchers. There are many more known sites than there is funding to excavate them so this one was likely known for decades before they got around to it.

These site inventories are generally filled using cultural resource management records submitted by surveyors, miners, construction companies, etc. who are often legally required to file them. A few tour guides I’ve used in Mexico found new ruins in the jungle and submitted their records with GOS coordinates and pictures. If locals knew about it, someone likely recorded the location a while ago.

This is fascinating, I had no idea it worked this way. I just always sort of assumed people happened upon random places that eventually make the news, not that there's a backlog of places to explore.

The backlog has actually gotten really bad in the last decade because of all the LIDAR surveys. There are many large settlements in the jungles of Central and South America that have been discovered in recent years that are both more expensive to study because they're so inaccessible and much larger so they're difficult to keep secret.