Ecto.Adapter.Queryable.prepare_query

You're seeing just the function prepare_query, go back to Ecto.Adapter.Queryable module for more information.
Link to this function

prepare_query(operation, repo_name_or_pid, queryable)

View Source

Plans and prepares a query for the given repo, leveraging its query cache.

This operation uses the query cache if one is available.