Someone's probably mentioned this, but I figured I'd throw it out there just in case.
I have a suspicion that Tia Dalma probably has some involvement. Read the post & you'll see that one of the treasure hunters says to "take it to her upriver" (which I'm assuming would be referencing Tia Dalma, since she resides in Pantano River in the game) Tia Dalma also had somewhat of a relationship with Davy Jones in the POTC movies, so I wouldn't be surprised if she had some other insight about his crew, his cursed blades & their secrets.
Opens up the possibility (in my opinion anyways) of there being another new questline or some information we haven't picked up on yet.
https://gyazo.com/60d1ac2fa20263fe64dd8ff7827ff6b2