Well, if that isn't throwing down the gauntlet, I don't know what else is

Bring it on rifters
I'd like to reiterate what a couple of others have said on here - no idea, and no amount of tinfoil, is too much or too silly......
There is a puzzle here, and we don't have all the pieces (yet). But it will come. We need to examine every clue and every lead. Some we'll discard, and some we'll hang onto. And slowly the pieces will reveal themselves, and we'll finally know the 'mystery of the rift'... and remember, we don't even know what 'it' is yet... a system? a wreckage? a sentient race, or a bigger mystery to solve?
I've been a little out of it this past week... will have to get foiled up and back on track
I've been listening to the Elite Reclamation audiobook all week and just got to chapter 10. A couple of things jumped out at me about the way the old lady tells her story to Salomé. At one point she says "I lost..." and then stops. What did she lose?
Also, when she says "there was some serious s**t out there, stuff you wouldn’t believe", and finishes "Ah, it’ll all come back to bite them one day, it’s all there in the Imperial databanks somewhere - and they thought the Thargoids were trouble" - it's entirely possible that the thargoid reference is referring to what's in the rift.