Open file with custom extension

I have an app, which should create and open files.

I added to manifest:

<activity android:name=".main.ViewActivity">
        <intent-filter>
            <action android:name="android.intent.action.VIEW" />
            <category android:name="android.intent.category.DEFAULT" />
            <category android:name="android.intent.category.BROWSABLE" />
            <data android:scheme="file" />
            <data android:host="*" />
            <data android:mimeType="*/*" />
            <data android:pathPattern=".*\\.fff" />
        </intent-filter>
    </activity>

But when I pick file from messenger or file explorer, it doesn't use my app to handle intent.

I also tried to add more path patterns, but it changes nothing.

Please help me with that!