It's generally nothing big enough to have heard of unless you're looking into whatever niche it fills.

Only example that comes to mind is mechanical keyboard stuff. For some of the smaller / one-off designs there was a habit of "if you need troubleshooting, here's a discord link" instead of even minimal documentation. For "standard" stuff that used the same lil microcontrollers as everything else just a minor annoyance, but saw it with ones that used custom / no microcontroller too, where even a "you need X diodes, Y sprockets, etc" would've been nice.

Like OP tend to see it and move on and forget about it because it's not worth it. The few times I really wanted to get some service running on a raspberry pi or arduino or whatever and tried the discord was a handful of 'regulars' swapping memes that were annoyed I wasn't intimately aware of their codebase.