The Silfrax Galaxy was the home galaxy of the Vespiforms. The Tenth Doctor stated that the Vespiforms had huge hives in this galaxy. (TV: The Unicorn and the Wasp)
On 9 September, 2367, the Vespiforms declared jam to be illegal in the Silfrax Galaxy. (PROSE: Time Traveller's Diary)
The Thirteenth Doctor once tried to go there, but the TARDIS malfunctioned and brought her and Lizzie to Brouhaha-Nine-Nine-Five instead. (PROSE: The Runaway TARDIS)