What does the attribute android:exported with values…

The android:exported attribute in the Android App manifest (AndroidManifest.xml) determines whether your app's components (Activity, Service, BroadcastReceiver, ContentProvider) can be accessed by other applications or processes in the system.

android:exported="true":

The component can be invoked or accessed from other applications.
For example, if an Activity is marked as exported="true", another application can start this Activity using an Intent.
This is necessary if your component needs to interact with other applications (e.g., providing data via ContentProvider, starting a service from outside).
When using Intent Filters with certain categories (e.g., android.intent.category.LAUNCHER), the component is by default exported="true", even if the attribute is not explicitly set or is set to false.

android:exported="false":

The component is only available within its own application or processes with the same user ID.
Other applications cannot directly access this component.
This setting is the default for most components on Android 12 (API level 31) and above if the component does not have intent filters.
Using exported="false" is a good security practice as it limits potential entry points for third-party applications.

<activity android:name=".MainActivity"
          android:exported="true"> // This activity is accessible from other applications
    <intent-filter>
        <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.LAUNCHER" />
    </intent-filter>
</activity>

<activity android:name=".InternalActivity"
          android:exported="false"> // This activity is only available within our application
</activity>

<service android:name=".DataService"
         android:exported="true"> // The service can be started externally
    <intent-filter>
        <action android:name="com.example.myapp.START_DATA_SERVICE" />
    </intent-filter>
</service>

<provider android:name=".MyContentProvider"
          android:authorities="com.example.myapp.provider"
          android:exported="false" // The provider is only accessible within the app
          android:grantUriPermissions="true"/>

What does the attribute android:exported with values 'true' and 'false' mean?