Both of you keep critiquing the shape of the knife matching the wreckage. Yes, that is stupid, but I’m not arguing for that (especially since it’s already been removed in v1). So please stop bringing that up.

I’m only talking about the Sith runes. Other people knew what a wayfinder was (because they are necessary for deep travel into the Unknown Regions) but he was the only one who knew where this Sith one was located. He was probably told by Palpatine about its location, though (ya know, since it belongs to him).

In canon, he bragged about it at Cantinas and that’s how it got to Lando, and by proxy Luke. He clearly only inscribed the runes for bragging rights. Nobody else could understand what was written on it unless they were from Exegol (or knew Sithspeak).