Hi there,
We don't actually have that information, as the channels are not associated with the ad unit itself, but rather with the generated ad code, which is a stateless process. This means we don't really store the knowledge of this ad-hoc association on our end; rather we just record impression-time stats that can be retrieved through reporting.
If you don't want to store this locally, you can always look into and parse the generated ad code, which I assume you're storing already?
Cheers,
Sérgio
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Sérgio Gomes
Developer Relations
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