Any estimates when is this going in and to be released?

Thanks for the PR! Unfortunately this makes the UIKit extensions available to all package consumers, not just those on iOS, so anyone who includes both packages and isn't on iOS will see a build failure. There doesn't seem to be a way to conditionalize the target so it's only available on iOS, which is why I didn't include it when creating the package in the first place. For that reason I'm inclined not to merge this PR and just say that anyone who wants the extensions should use other package managers, unless there's an alternate solution.

As someone who consumes platform-dependent packages from multiple platforms, I know there are many mechanisms to remove the difficulties presented here. You could have a specific target just for macOS/AppKit or watchOS/WatchKit, or you could surround imports with compiler conditionals. Merging this will not break existing code, and those requiring it will be able to easily overcome any challenges they face including it.