network, advertising network, search engine, or email service that participates in the voluntary online terrorist content moderation exercise program under this Act. (7) The term Tribally controlled college or university has the meaning given such term in section 2 of the Tribally Controlled Colleges and Universities Assistance Act of 1978 ( 25 U.S.C. 1801 ). (k) Sunset The authority to carry out this section shall terminate on the date that is seven years after the date of the enactment of this Act. 3. Comptroller General report Not later than 180 days after the Comptroller General of the United States receives the sixth report under section 2(f), the Comptroller General shall submit to Congress a report on the implementation of section 2.