A couple of 'firsts' here. First woman, first African-American, but not the first librarian according to the Washington Post.
In addition, the law was changed last year to make the Librarian of Congress appointment a ten year term, and the thought has been expressed that Congress may be more comfortable waiting and allowing the voters and next president to make this appointment via the electoral process, rather than the current one.
https://www.washingtonpost.com/lifes...82d_story.html