freeTier property
Background: Free tier is the ability of a Firestore database to use a small amount of resources every day without being charged.
Once usage exceeds the free tier limit further usage is charged. Whether this database can make use of the free tier. Only one database per project can be eligible for the free tier. The first (or next) database that is created in a project without a free tier database will be marked as eligible for the free tier. Databases that are created while there is a free tier database will not be eligible for the free tier.
Output only.
Implementation
core.bool? freeTier;