I've always wondered about the CBM in this instance. Isn't that technically an opaque horizon of light? I understand that it's not stars per se, and that there

I've always wondered about the CBM in this instance. Isn't that technically an opaque horizon of light? I understand that it's not stars per se, and that there is technically stuff "beyond" that, but doesn't that count as a "bright" night sky? Just not in the visible spectrum.