katos I believe that the extension may potentially be rewritten.
I've taken over the responsibility (again) over koseki. The extension I am working on for my (new) employer Bokt will be released under its own name bokt/flarum-categories. Once it's done, Koseki will be abandoned in favor of this new extension, this was discussed with team reflar.
The idea behind the bokt version is to offer more flexibility and an even deeper categorial layout.
No estimation of release yet.
