Multiple realities(covers information from several alternate timelines)
The Zahl homeworld was an inhabited planet located somewhere in the Delta Quadrant, home to the Zahl civilization.
In 2374, all traces of sentient life on the planet were erased from history by the Krenim weapon ship. They were restored when the weapon ship was, itself, erased from history. (VOY: "Year of Hell")
This planet was only mentioned in dialogue.