[Zenity]

Yes it is using its own parsing engine. The developer is prioritizing the most common language features but also constantly working on adding more edge cases as people run into them. The parser is designed to do a sensible thing in all cases, so while occasionally it may not get it perfectly right (yet), that doesn't break the parser completely.

What this custom solution is doing that others don't is simply that it is incredibly fast. You really need to try it to fully appreciate this though, especially on large codebases it makes a significant difference. Not just because it never lags or stalls while working, but also because it makes it much less painful to work with those codebases if you can instantly find and jump to anything.

The speed and simplicity is the main selling point, but unlike other lightweight editors it doesn't achieve this simply by being "less". From my perspective the main selling point is that it is a lightweight and performant editor that can actually replace Visual Studio + VAX / JetBrains for game developers (especially Unreal Engine projects and comparably large codebases). For that use case there just isn't anything comparable on the market right now.

Whether it is equally useful in other scenarios already (especially if you are happy with your current setup) I can't really judge, and I would agree that the website could do a much better job selling it. The developer is still updating the website often, but his priority is working on the actual app of course and he is doing everything by himself from what I can tell.

In a nutshell, right now I would say that 10x is mainly a great choice for game developers. But that's only because that is where its strengths are most unique right now, not because it is intended to be only that. It still isn't even fully released yet, and I think it has a lot of potential to be much more than "just" a performant editor for game developers.