It's SuperAdmin-only. Flagging a user as an Onboarder exempts them, like SuperAdmins, from the mandatory two-factor-authentication popup and the Terms & Conditions acknowledgement popup that otherwise interrupt admin users — it's meant for Sprwt's own onboarding staff working inside a client account, not a customer setting. (In the current version, the mandatory-2FA popup itself only targets a specific admin role, but SuperAdmin and Onboarder are always exempt from both popups.)