See https://github.com/TeamNewPipe/NewPipe/issues/6577#issuecomment-876095378
java.lang.ClassCastException: android.widget.ImageButton cannot be cast to androidx.appcompat.widget.AppCompatImageButton
at org.schabi.newpipe.player.Player.onRepeatModeChanged(Player.java:2263)
at com.google.android.exoplayer2.ExoPlayerImpl.lambda$setRepeatMode$2(ExoPlayerImpl.java:564)
at com.google.android.exoplayer2.-$$Lambda$ExoPlayerImpl$rgrcbaqP9Y8LgzdByBnAfUO4ydU.invokeListener(lambda)
at com.google.android.exoplayer2.BasePlayer$ListenerHolder.invoke(BasePlayer.java:279)
at com.google.android.exoplayer2.ExoPlayerImpl.invokeAll(ExoPlayerImpl.java:1498)
at com.google.android.exoplayer2.ExoPlayerImpl.lambda$notifyListeners$6(ExoPlayerImpl.java:1318)
at com.google.android.exoplayer2.-$$Lambda$ExoPlayerImpl$b59raXxaB-trjwE5bgpZInm1QnU.run(lambda)
at com.google.android.exoplayer2.ExoPlayerImpl.notifyListeners(ExoPlayerImpl.java:1328)
at com.google.android.exoplayer2.ExoPlayerImpl.notifyListeners(ExoPlayerImpl.java:1318)
at com.google.android.exoplayer2.ExoPlayerImpl.setRepeatMode(ExoPlayerImpl.java:564)
at com.google.android.exoplayer2.SimpleExoPlayer.setRepeatMode(SimpleExoPlayer.java:1636)
at org.schabi.newpipe.player.Player.setRepeatMode(Player.java:2253)
at org.schabi.newpipe.player.Player.onRepeatClicked(Player.java:2232)
at org.schabi.newpipe.player.Player.onBroadcastReceived(Player.java:1123)
at org.schabi.newpipe.player.Player.access$200(Player.java:190)
at org.schabi.newpipe.player.Player$3.onReceive(Player.java:1060)
at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:1185)
... 7 more
AppCompatImageButton ignores "tint" theme attribute on API 19, therefore, they had to be specified directly, these attributes can be removed after the KitKat support is dropped.
