tachiyomi/app/src/main/res/drawable/ic_expand_more_24dp.xml

<vector xmlns:android="http://schemas.android.com/apk/res/android"
    android:width="24dp"
    android:height="24dp"
    android:viewportWidth="24"
    android:viewportHeight="24">
    <path
        android:fillColor="@android:color/black"
        android:pathData="M16.59,8.59L12,13.17 7.41,8.59 6,10l6,6 6,-6z" />
</vector>