Does anyone know where the small interior A/C recirculation filter goes?

[Xtony]

I searched and nobody seems to know where it gets installed. I know that on my old 7 series that had two of those they would get filthy fairly quickly despite having clean cabin filters under the hood.

I asked my dealer if those filters would get replaced before my included (lack of) maintenance expires and he said no, so so far I've replaced the engine filters and the cabin filters under the hood.