It's fine to keep the director's cut trailer in this entry.

So the separate entries for the director's cut are already deleted? I wonder why though, if this one is allowed https://www.themoviedb.org/movie/791373-zack-snyder-s-justice-league, they should be allowed too. Both are significantly longer and announced to be very different from the regular version.

Alternative versions (director's cut) are not supported. Exceptions to this rule are very rare and any alternative version added without Travis' approval will be deleted. I don't know why the entry for Zack Snyder's Justice League is allowed to stay in the database, so I asked internally and will reply to this report once I get an answer.

Yeah, I know about the rule. I didn't add it, just stumbled upon it. But since this particular one is being promoted as about 1.5 times longer than the original version, with different scenes filmed especially for the director's cut, different age rating, etc I thought it worth asking. I think I already know the answer, but thanks for clarifying that.

Well, I can't give you an exact reason why that movie was allowed to remain in the database because I couldn't get any concrete details. I tried searching in some internal threads but they are huge and I couldn't find anything. An experienced mod told me that this is decided on a movie-by-movie basis, and Zack Snyder's Justice League was probably allowed to remain in the database because it was an anticipated and popular cut. My guess is that probably users kept adding the entry over and over again, so mods and Travis decided to keep the entry, but this is just my guess because I wasn't present on TMDB at the time. If I ever come across exact details on this, I'll try to reply here. Finally, one thing for sure is that allowing alternative versions is very rare and an exception does not open the door to all alternate cuts.