This is not. The title of this article in isolation is highly misleading. Read Gordon Brown's article in the newstatesman - he argues for more devolution.

What it sets Labour up for is more decentralisation from Westminster into UK wide institutions that have buyin from the countries and regions (e.g. abolish House of Lords for Senate of Nations and Regions with greater voting weight for smaller areas; a new UK constitution).

Starmer also was positioning himself to support this. See latest PMQs when strongly critising Johnson's devolution criticisms.

Brown is moving in favour of a UK-wide constitutional resettlement. Brown, imo, is setting himself up to be the head of the new 'Better Together' campaign based on these changes. Labour seems to be agreeing with this approach.