What is the fine-grained topic of the following text: BassBuds™' UK launch in March 2013 was as sponsors of “The Show Tour” celebrating 90’s RNB stars with a line-up that included musical groups: SWV, Dru Hill, Blackstreet, Damage, Jodeci, and Changing Faces. Only return the topic.
BassBuds™ UK launch as sponsors of "The Show Tour" in March 2013