For the most part, Ferris Bueller's fourth wall breaking in Ferris Bueller's Day Off is just a quirk of narration. Instead of having the character deliver a voiceover, he speaks directly to the camera. Although this isn't necessarily an acknoweldgement that he's living inside a movie, it does break the reality a little.
But, like a lot of the movies on this list, the largest fourth wall break comes at the end of the film, specifically after the end credits. Obviously back in the pre-MCU days, people had no reason to stick around for the credits (apart from, you know, wanting to see who worked on the film), so Broderick's post-credits return would have been mostly missed by a cinema-going audience.
It's brief, but he quite simply tells us that the movie's over, and that we should go home. Good advice.
Interestingly, in the short-lived TV show adaptation of the movie, Ferris is played by Charlie Schlatter, and in his reality, Ferris Bueller's Day Off was based on his real life, and he openly discusses his annoyance at having been played by Broderick, complaining he was 'too white bread'.
Unsurprisingly the show was cancelled after one season.