Regs object
Regs carries the legal and regulatory signals that apply to a bid request: the COPPA flag, whether GDPR applies, the US Privacy string, and the Global Privacy Platform string with its applicable sections. It sits at BidRequest.regs. OpenRTB 2.2 called the same object Regulations.
How it is used
Several of these signals began as extensions and were promoted later. OpenRTB 2.6 moved regs.ext.gdpr to Regs.gdpr and regs.ext.us_privacy to Regs.us_privacy, and 2.6-202211 added Regs.gpp and Regs.gpp_sid. Send each signal at the location that matches the version you declare. Regs only states which rules apply; the TCF consent string itself goes in User.consent.
The Privacy signals page covers it in more depth.
Fields
Where it sits
Contained in: BidRequest.
All objects
The field reference index lists every OpenRTB 2.x object.