We do not use these dlls in Sitefinity 4.2 build. You can remove them. Please check if you have some reference to the dlls from custom class libraries or custom implementations.
the Telerik team
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items