Usage of android process

Question

I have this AndroidManifest.xml file:

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
android:versionCode="1" android:versionName="1.0.0.0721"
android:process="com.lily.process" package="com.lily.test">

    <provider android:authorities="com.lily.test"
      android:name="com.lily.test.provider" 
      android:process="com.lily.process">
    </provider>

"android:process" is included in both the manifest and provider tags; from what I can see, the provider can execute in the "com.lily.process" process if it is added to the provider tag. But what purpose does it serve when expressed as a manifest tag? I attempted executing all of the components in the process it listed, but it wasn't possible.