With PolicyKit version 1.0 it got renamed to polkit. PolicyKit (version lower than 1.0) aren't any longer in the portage tree. Googleing for PolicyKit brings up a lot of old crap So, the global "policykit" USE flag should be also renamed to "polkit". Reproducible: Always
policykit - Enable PolicyKit authentication support app-emulation/virt-manager:policykit - Enables sys-auth/polkit authentication support, required when using app-emulation/libvirt with PolicyKit authentication net-misc/spice-gtk:policykit - Enable sys-auth/polkit support for the usbredir acl helper sys-auth/consolekit:policykit - Use the PolicyKit framework (sys-auth/polkit) to get authorization for suspend/shutdown.
Strong no from me here. The framework and APIs are still PolicyKit and the top 10 links on Google for "PolicyKit" are all still correct and valid. Every distro refers to their PolicyKit integration. It just happens to be that the package on Linux that provides PolicyKit backend APIs is called "polkit" to decouple it from the API/framework. So it logically makes sense there's two different names.
Strong no from me as well. USE flags ought to describe functionality, not just carry the name of the external dependency commonly pulled in for it. policykit is vastly better name than polkit - unlike an abbreviation like "polkit", it actually clearly describes the functionality without having to figure out the abbreviation - policy management.
no useless renaming. USE="policykit" is suitable.