There isn't a centralized "review center" specifically for TOEFL examiners in the way there are for TOEFL test-takers. Becoming a TOEFL examiner involves a rigorous selection process conducted by ETS (Educational Testing Service), the organization that administers the TOEFL iBT. This process includes extensive training and assessment on the specific scoring rubrics and protocols for evaluating the different sections of the TOEFL test (reading, listening, speaking, and writing).
While there aren't dedicated review centers, the ongoing training and professional development provided by ETS to its examiners serves a similar purpose. This training is crucial to maintaining consistency and accuracy in scoring across all test administrations. Examiners regularly receive updates and participate in professional development activities to ensure they're up-to-date with the latest testing procedures and scoring guidelines.