godot/platform/android/java/lib/res/mipmap-anydpi-v26/icon.xml

<?xml version="1.0" encoding="utf-8"?>
<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
    <background android:drawable="@mipmap/icon_background"/>
    <foreground android:drawable="@mipmap/icon_foreground"/>
    <monochrome android:drawable="@mipmap/icon_monochrome"/>
</adaptive-icon>