What happened to the X Rating?

MPAA X Rating, Scary Logos Wiki

cinema history - Why would a movie that appears pornographic via it's rating (X) receive an Academy Award? - Movies & TV Stack Exchange

getTV - The movie ratings system began 51 years ago today — Nov 1, 1968. The first ratings were: G — General Audiences M — Mature (became PG) R — Restricted X —

Best X-Rated Movies: Adult Movies That Are Actually Good - Thrillist

Rated X | Sticker

Canyon Rating System - Road Trip Ryan

Saw X - Rotten Tomatoes

X-Rated Movies: 28 Provocative Films That Challenged the MPAA – IndieWire

X-rated Royalty Free Vector Image - VectorStock

Acer Swift X (AMD) Review