Provides a layout library allowing content editors to pick from a list of pre-defined layouts.
Site builders can create and deploy pre-defined layouts for each entity-type and bundle combination.
Content editors can pick from existing layouts.
Site admins can prevent content-editors from creating their own bespoke layouts but give them the ability to customise layouts on a per-content-item basis.
Layout builder (in core)
Layout discovery (in core)
Field UI (in core)