react-native-test-app/android/app/src/main/res/values/colors.xml

react-native-test-app provides a test app for all supported platforms as a package

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="colorPrimary">#008577</color>
    <color name="colorPrimaryDark">#00574B</color>
    <color name="colorAccent">#D81B60</color>
</resources>