The following is research that was done for my post titled “The K’un-Lun of Netflix’s Iron Fist [Within the Larger Context]”, as a means of supporting one of my points. Due to its length I decided to dedicate another short post to it to avoid adding to what was already too lengthy an article.
I would encourage you to read that one in full, though this should certainly be interesting enough on its own.
For the vast majority of my blog posts about Marvel comic books I refer to the Marvel Database, an unofficial wiki updated by fans. While that format can and does lend itself to the occasional error, the citations at the bottom of the page referring to specific runs and issue numbers allow for fact-checking if needed. At this point in time there are no direct mentions to K’un-Lun being anything other than one of the Capital Cities of Heaven, besides a heading for the alien race the H’ylthri with no text underneath it.
However a number of other sources have slightly differing origins. Comic Vine, another well-regarded comic book wiki, mentions on its entry for the city that:
“K’un-Lun is the stronghold of a colony of humanoid aliens, place of origin unknown, whose spaceship crash-landed upon a small, extradimensional world, approximately a million years ago.”
Unfortunately there are no citations listed anywhere. This tidbit of information is also listed on Marvel Directory, a largely defunct site that appears to have been last updated in 2015. Their entry categorizes K’un-Lun as an “Alien world” and only refers to the issue where the location first appeared, Marvel Premiere #15. As far as anything from Marvel themselves, the page on the publisher’s own wiki currently does not exist.

Power Man and Iron Fist Vol. 1, #69. Written by Jo Duffy and Steven Grant, illustrated by Alan Weiss.