This extension is for "pure" Swift development, not iOS development. I doubt the latter will ever officially happen. It's possible to make it work for iOS at an unofficial capacity though by hooking into the extension's LSP support. We did this at Spotify to enable iOS development in Cursor for Bazel iOS projects: https://github.com/spotify/sourcekit-bazel-bsp

This is a very welcome improvement but I should note the title is a bit clickbaity: using Swift on e.g. Cursor was always possible, it's just that after Microsoft banned forks from accessing the official VSCode marketplace last year you started having to workaround it by downloading and installing the .vsix file manually. Having the extension on the Open VSX Registry sorts this out so you can now install it via the proper way once more. Very happy this finally happened!