This is any priest. For example, the priest of our parish comes from the Philippines. He is not SSPX, or anything else - he is just an ordinary priest in full communion with Rome. He had to apply to the Bishop of Calgary to get permission to say Mass and perform the Sacraments in Calgary.
The same thing happened with our associate pastor, who comes from India. He arrived last summer, and before he was even allowed to move in to the Rectory at our church, he had to get permission from the Bishop to work as a priest in Calgary.
Whenever I travel with Father M., he always has to carry a paper that says he is a priest in the Diocese of Calgary, and that it is okay with the Bishop of Calgary if he performs the Sacraments in other cities. Before he can do that, though, he has to show the paper to the local Bishop there, and get permission from that Bishop, as well.
That’s why our first stop whenever we take him anywhere is the Cathedral Church of the place where we are spending the night - so that he can say Mass for us, and hear our Confessions.