Decennial Census 2000/2010 SF3 API?

Does anyone have any insight on why the 2000/2010 SF3 API endpoints do not exist anymore? Only SF1 variables are available, though 2000/2010 SF3 APIs did exist in the past.

This link is now 404: https://api.census.gov/data/2000/sf3.html

No explanation is offered here:

https://www.census.gov/data/developers/data-sets/decennial-census.2010.html