The CA/BF has a history of terrible decisions, for example 2020's "Baseline Requirements for the Issuance and Management of Publicly-Trusted Code Signing Certificates".

Microsoft voted for it, and now they are basically the only game in town for cloud signing that is affordable for individuals. The Forum needs voting representatives for software developers and end users or else the members will just keep enriching themselves at our expense.

How is the CA/B forum relevant for code signing certificates?

How are they not? :)

They set the baseline standard for code signing certificates. In 2020 they added the requirement to use hardware modules which resulted in much higher prices and fewer small developers opting to sign their code.