The bill titled "An Act relative to courthouse court officers" proposes amendments to Chapter 221 of the General Laws of Massachusetts. Specifically, it seeks to replace section 70A with new provisions that grant court officers and those authorized to act as court officers the ability to perform police duties and exercise police powers within court premises and their immediate vicinity. This authority is contingent upon designation by the chief justices of the trial court, supreme judicial court, or appeals court. 
Additionally, the bill stipulates that court officers may carry weapons as deemed necessary by the respective chief justices while on court premises or in the immediate vicinity. However, it mandates that any court officer wishing to carry a firearm within a courthouse must possess a valid license to carry, as outlined in sections 131 or 131F of chapter 140. This amendment aims to enhance security measures within courthouses while ensuring that court officers are properly licensed to carry firearms.