The wiki for cleft_of_venus mentions it's a specific part of a pussy, but it uses anatomical jargon that the average user (and even experienced users) aren't going to understand and because of a lack of examples it proved very difficult to figure out even after a lengthy discussion on the Discord server. Some suggestions included the area between the pubic hair and the actual opening, the Y shape sometimes seen at the top of a pussy, when a pussy is drawn in a (|) shape, or simply when the pussy is "neat without bits coming out".
I'd like to clarify exactly what this tag is for, and if it turns out everyone has their own definition of the tag then I would support nuking it. That being said, if it has a distinct appearance and a generally unified usage then all that's needed is a wiki page for users who don't have a degree in anatomy.