Google Cloud's business intelligence platform for exploring data, building dashboards and reports, and defining reusable business metrics with LookML. Looker Studio (formerly Data Studio) is the free version for simple dashboards.
In CDL it represents data democratization: business users without SQL skills explore data from BigQuery and other sources. Question: the marketing team wants interactive dashboards without writing code → Looker Studio; governed metrics for the whole company → Looker.
Looker is a concept that can show up on the exam. Check the full guide to see it in context.