I have all basic features working and am mainly going to focus on polishing it before the release.
It should now be generally safe to test, but I still only recommend it if you have a backup of your files. (Which you should create anyway :blobfoxevil:)
Please report all bugs you find, any features that are missing and improvements you would make!
And I thought I could document the development process here.
I've wanted to explore the idea of a non-hierarchical file manager for a long time and this is the result, Hyperplane.
The idea is that you organize files by tags (or categories or whatever name I end up with) instead of folders while still being able to access them from a traditional file manager.
You can test it now if you want, details in the README: