LibreTube/app/src/main/res/drawable/ic_add_instance.xml

<vector xmlns:android="http://schemas.android.com/apk/res/android"
    android:width="24dp"
    android:height="24dp"
    android:tint="?attr/colorControlNormal"
    android:viewportWidth="24"
    android:viewportHeight="24">
    <path
        android:fillColor="@android:color/black"
        android:pathData="M4,6L2,6v14c0,1.1 0.9,2 2,2h14v-2L4,20L4,6zM20,2L8,2c-1.1,0 -2,0.9 -2,2v12c0,1.1 0.9,2 2,2h12c1.1,0 2,-0.9 2,-2L22,4c0,-1.1 -0.9,-2 -2,-2zM19,11h-4v4h-2v-4L9,11L9,9h4L13,5h2v4h4v2z" />
</vector>