The short answer
Yes. Rebuilt or re-downloaded automatically when needed.
What is it?
Kotlin/Native, used by Kotlin Multiplatform to build for iOS and other native targets, downloads its compiler and large dependencies (an LLVM toolchain, platform libraries, sysroots) into ~/.konan. A version is added for each Kotlin release you build with, so the folder typically reaches a few gigabytes.
Compilers and dependencies Kotlin Multiplatform downloads. Downloaded again on the next build.
What happens if you delete it?
Everything is downloaded again on the next Kotlin/Native build, which makes that build much slower and needs a network connection. Your projects are not affected.
How to remove it properly
Stop Gradle with ./gradlew --stop and quit your IDE, then move ~/.konan to the Trash with Finder’s Go › Go to Folder…. Removing only the kotlin-native-prebuilt-… folders of old Kotlin versions is a gentler option.
Quit the app that uses it, then move it to the Trash. Empty the Trash when you’re sure.
How MoreRoom helps
MoreRoom recognises this item, shows its real size and when it was last used, and labels it “Safe to remove”. In the free version you can move it to the Trash in one click, with Undo; Pro collects every safe item at once.
Frequently asked questions
Is it safe to delete the ~/.konan folder?
Yes. Rebuilt or re-downloaded automatically when needed. Everything is downloaded again on the next Kotlin/Native build, which makes that build much slower and needs a network connection. Your projects are not affected.
Will Kotlin/Native toolchains come back after I delete it?
Yes. Everything is downloaded again on the next Kotlin/Native build, which makes that build much slower and needs a network connection. Your projects are not affected.
How do I remove Kotlin/Native toolchains properly?
Stop Gradle with ./gradlew --stop and quit your IDE, then move ~/.konan to the Trash with Finder’s Go › Go to Folder…. Removing only the kotlin-native-prebuilt-… folders of old Kotlin versions is a gentler option.