It could be a wireless lapel mic, but again it makes no sense to shove the mic pack into a knee high boot. She does have a mic clipped on her right side collar where the white undershirt meets the sweater. Megan and Harry have mics as well, but their mic packs aren’t bulging out on their bodies. They could hide and access the mic pack much easier if it’s not shoved deep into her boot. If it is a mic pack it could be placed in several other places on her or around chair so they could have quick access to the pack if needed.