When the ChaoShan people introduce their Gun Who Theh (工夫茶) to the rest of China, they communicate in Mandarin, the official dialect of the country, and introduce 工夫茶 as Gōng fū chá. Remember I said the term 工夫 is not used outside of the ChaoShan area? So when the Mandarin or Cantonese speakers hear gōng fū chá they natually think of the commonly used written term of gōng fū - 功夫. 功夫 has two broad meanings: 1. martial art, or, 2. skills. So when 工夫茶 is mass marketed to the general Chinese consumers and to the rest of the world by people who don't understand the Teochew dialect, it becomes 功夫茶, or martial art tea! Interesting right? Another classic example of lost in translation.
So when I see tea label like this, I always joke that drinking it would make you a black belt. Really, it's what the label suggests.