tl;dr: StreetComplete, the OpenStreetMap editing app, is being ported to iOS using Kotlin Multiplatform and Compose Multiplatform, allowing most of the existing Kotlin codebase to be reused rather than rewritten (as would be needed with Flutter). The migration—estimated at roughly one man-year of work—is about 50% complete after full-time work in early 2024, and the maintainer is seeking contributors and sponsors to finish the remaining work tracked on a public project board.