_onlyOwner, NotGuardian, NotCore, NotModule, NotProposer, and NotKey. The contracts do not use onlyTimelock as a modifier name. Registry writes go through owner(), which is the timelock.
Related: Governance, Security.
Access controls
Every privileged function and who can call it, scanned from the contracts.
Privileged calls are explicit in the source. This page lists each one and the role that can send it.
The scan looks for