Change how the Rerun viewer looks by writing a blueprint, for a recording or for a table. Read this whenever asked to change the look of the viewer, such as laying out a recording or dataset, designing a default blueprint, deciding which views show which entities, or making a segment or catalog table look nice by hiding columns, changing column order or filtering rows. Covers archetype-to-view mapping, layout reasoning, the rrb construction API, the contents grammar, table blueprints, and the screenshot loop.