OFFICIAL PAGE: KoeKestra
KoeKestra is a Japanese web-based service for separating an audio source file. According to the website, KoeKestra is "a service that removes and extracts vocals from songs with vocals. Using the latest deep learning technology, we have achieved the world's highest level of accuracy" (according to their own research). For more details visit the website at the above link using Google Translate.
Screenshot courtesy of KoeKestra.com