I had a thought, and have followed it up a little.
The mission from the Dark Wheel gives some text:
"Mission 2 mentions a rumour that talks about: "A Certain celestial body. Place that isn't a place, door that is also the key. The myth." Upon delivery you receive a message mentioning a map and a context for coordinates."
I decided to look into words to work from, that meant what we were looking for in this riddle.
"Door that is also the Key" = from Latin; "clustrum" means bar, key, bolt, enclcosure, door - a few other things.
What if that rumour is actually more than just a rumour; perhaps a clue, set to mark that path?
I searched the map for anywhere with the name clustrum, but haven't hit anything yet. Same result, with EDSM. That doesn't mean its not a planet, or undiscovered, or maybe that we need more information to put it together.
And, mentioned in non-canonical lore, a theory was put forth that Raxxla may be a rogue planet. The navicomputer assigns a location based upon their stellar body; therefore, a rogue planet is a place, but our computers wouldn't see it as such.
Such a place would also be seen as a Certain (capitalisation important?) celestial body, potentially.
I'd love to hear some thoughts. Is this a chain worth pursuing? Has it been pursued before?