This is Apple Health, it's built-in. It's most accurate for Apple or Beats headphones, but works for any device ever connected and recognised as audio device. If OP scrolls down that list it'll show 'Filter by Headphone Type' which for me has AirPods, AirPods Pro, BC-06, EarPods, HY82.
BC-06 and HY82 are Bluetooth car kits, so the generic dB estimates for those are likely based on volume usage which in this specific case certainly varies from what it actually was (since they were car speakers, but Health doesn't know that), whereas the data for their own devices is likely correct provided the device is functioning as expected.
This is Apple Health, it's built-in. It's most accurate for Apple or Beats headphones, but works for any device ever connected and recognised as audio device. If OP scrolls down that list it'll show 'Filter by Headphone Type' which for me has AirPods, AirPods Pro, BC-06, EarPods, HY82.
BC-06 and HY82 are Bluetooth car kits, so the generic dB estimates for those are likely based on volume usage which in this specific case certainly varies from what it actually was (since they were car speakers, but Health doesn't know that), whereas the data for their own devices is likely correct provided the device is functioning as expected.