Why fragments and views doesn’t obfuscate?

Although Fragment and View classes aren’t android MainComponent and no reference of them in AndroidManifest.xml, classes that extend Fragment/View don’t change their name/package when minify is enabled and Proguard is working well?

Why they don’t obfuscate?

PS1: The other codes obfuscate completely (change name/package/methods/attributes)

PS2: The above classes just obfuscate their methods and attributes. (Not name and package)

Source: Android Questions