As explained on various website:
Jeff Casey, Alberta, Canada shared '1884" seeds with Tatiana Kouchnareva, a tomato collector in 2005. Both Jeff and Tatiana grew it in 2006 and obtained large dark black-purple fruits which, in Tatiana's opinion, were better than the original 1884. Tatiana named it "1884 Purple" to indicate the fruit color difference compared to1884. Jeff Casey later suggested an alternative name - "Purple Doughnut". However, Tatiana had already listed this variety in the SSE Yearbook as "1884 Purple", and received several SSE requests for the 1884 Purple seeds in 2007.
