One of the vastly appealing aspects of Chris Claremont's legendary X-Men run were the little mysteries that the writer would ocasionally drop into the saga, and then just leave them sitting there for years and years.
Brilliant in hindsight and undeniably frustrating at the time, Claremont was playing the long game, and left loads of things hanging that were never really explained. He could have Jubilee find an old photo of Wolverine from many years ago, where he's standing in front of some huge futuristic city, and then just move the hell on. (Jubilee's fatphobia hasn't quite aged so well.)
Sometimes it paid off - and after having the mysteries of the Shadow King bubbling away for years, it would all climax with some bloody big explosions on Muir Island - and sometimes it was just some weird aside that could mean anything, because you weren't getting any answers here, bub.
Of course, the original Claremont X-Men ended more than three decades ago now, and I have little doubt that many of these thing were probably answered in one of the thousands of X-Men comic books that have been published since, buried in some bullshit New Mutants mini-series from 2004 or something.
I don't know about any of that, all I have is the enjoyment of this long game when I go back and read these comics, and the way these mysteries could evolve and expand, or be clouded in more revelation, as the months and years rolled on. I'm not going to look it up on wikipedia or anything. I'm happy to let the mysteries remain.