Support for reading and writing mindfulness data to Health Connect is available right now in Android 16 DP1 but will be coming to older versions soon.
If you use multiple different health and fitness tracking apps on Android but want to keep all your information in one place, then you'll want to use Google Health Connect to aggregate your data. Health Connect is a service that simplifies data sharing between health and fitness apps so you can easily check up on your info as well as manage access to your data all in one place. However, apps can only share data that Google designed Health Connect to handle, so some entries, like those for your yoga and meditation sessions, haven't yet been supported. Thankfully, that's changing with the next version of Health Connect.