Collapsible Categories
What do you want
The ability to collapse channel categories like the native discord client.
Why
I believe this feature would help organize discord servers with many categories.
Implementation hints
Hitting enter would expand or collapse a category. Formatting like nerdtree

Seems like the API wrappers for this are still missing, so not sure when I am gonna do this.
NVM, doens't look like there's an API at all for this. Seems to be clientsided. If someone thinks differently, correct me please :D
So I am going to implement this locally.
Actually there is, but accessible only from user settings: https://luna.gitlab.io/discord-unofficial-docs/guild_folders.html
@pjeanjean those are Guild Folders, not Channel Collapse-States. Different thing. Thanks for the link either way, didn't know that project.
Oops, my bad, I was a bit tired and honestly assumed the issue was about server categories implemetation...
Collapsed categories do not sync, they are indeed client side (both for channels and server folders)
Sorry for the mistake, at least I'm glad I found the API documentation project (even better if it helps you ^^')