An analyst changes the attribution model for their Google Analytics property from Last click to Data-driven. Which dimensions will reflect this new attribution setting?

The property's attribution model applies to dimensions without a scope prefix, such as Source and Medium. Those unprefixed dimensions are the attribution-scoped ones: they describe which channel was credited for the key event under the model the property is configured to use, so changing from last click to data-driven changes what they report. Prefixed dimensions behave differently by design. 'First user' dimensions always record how the user was originally acquired, and 'Session' dimensions always record the source of the session in which the activity happened; neither depends on the attribution model. Knowing which family a dimension belongs to prevents a common confusion — an analyst who changes the model and then checks 'Session source' will see no difference and conclude the setting did not work, when they are simply looking at a dimension the model never touches.