A developer defined a new table in db.

If a developer wants to allow the removal of columns from the database when deleting them fromdb.schema.xml, they need to define the removable columns in thedb_schema_whitelist.jsonfile. This file will tell Magento which columns can be removed from the database.

To allow columns to be removed from the database when they are deleted fromdb_schema.xml, they must be listed in thedb_schema_whitelist.jsonfile. This file acts as a reference for which database schema elements are safe to modify or delete, providing a safeguard against unintentional data loss during schema updates.