Why intent extras key name should starts with package name in android?

Question

I am a beginner android developer, please consider it.

According to Android Docs, Intent EXTRA key should starts with package name but in my case it works with or without package name in extra name.

Example 1st (According to Android Docs) :- public static final String EXTRA_NAME = "com.example.firstmultiscreenapp.extra.name";

Example 2nd (Which also works) :- public static final String EXTRA_NAME = "name";

Please explain, why it is recommended that, Intent EXTRA key should starts with package name, else it also works without package name.

I am very curious about it, Please answer my question.