ThyTTY

What else could he say to not be thrown out? Dude works at Microsoft

IntelliJ has source available here under Apache-2 license. AFAIK only Pro edition is proprietary.

Android Studio has no source but there is one for Android IntelliJ plugin here.

Maybe I’m missing something but to me these cases are pretty different.

You can use IntelliJ Community to develop Android apps with an Android plugin.