This is a referendum to upgrade Kusama to v1.4. See the fellowship release notes for more details.
Of special note is enabling nomination pools participation in governance, removing funding to Kappa Sigma Mu Society, allowing burn parameters to be set via OpenGov, lowering parachains and data deposits on Kusama, adding all assets in pool with native xcm payment on Asset Hub, delegate stake pools in Kusama and improving bridges usage.
Enactment is set for block 27155056 around 8am UTC on 19th Feb
Edited to fix an error and to add the enactment date.