BigT29 wrote:As said, it supports a single custom word list already and from what I've seen this feature should also be in the IoS/Macos version. assuming they both use wordlist.ini (what the windows version uses)
This is the point I keep making. macOS and iOS use the built-in OS-provided spelling system which doesn't use wordlist.ini, nor does it (as far as I am aware) give you direct access to where the learned words are stored. You get API calls that your application makes, but it's the black-box OS service that does the actual checking.
Windows, of course, doesn't have such an OS-provided service, so the Scrivener implementation for Windows uses a third-party system. That third party system is not designed to provide per-project word lists, but because it's bolted on you have the workaround of seeing where the word list file is stored.