Traveller.
Not sure what this comment was in response to, but Traveller is a good counter example. Despite their being at least 7 version of that game, there is no equivalent to the OSR. People use products from all those versions interchangeably and there is no version purity tests (at least that I can see)
Classic Traveller, the original 1977 edition is considered the original edition. It differed significantly from the later 1981 edition, in that it did not feature a central campaign setting,
"The Imperium" but instead was more of a hard science based Space Opera / pulp Sci-Fi setting where one could create their own sector set at anytime and anywhere in the far future. The original rules included everything needed, for example, to make a Star Trek campaign, with matter transporters, phasers, photon torpedoes, and warp drives. Anything, for example Tech Level 15 or above, is right off the charts in terms of science fiction, and into the realms of science fantasy. Not many people chose to play Traveller that way though with such high tech levels.
It also featured a random jump-route generation system, which was very useful to create pocket space empires, or subsectors, and which was removed from the later editions of Traveller (1981+) that featured the pre-mapped Imperium including the other sophonts of the Solomani Sphere, The Hivers, The Vargyrs, The Aslan, the Droyne, and the Zhodani.
Original Traveller also did not have
Yellow or
Amber Zones, becuase there was no
Imperium, or vast Intergalactic government. It was up to the individual game referee to create their own far future setting, and include what they wanted in it. Of course, Just like with D&D, that all changed with the organized convention play of the late 70's and early 80's.
...and
Samardis Press produces the new open source original
Traveller clone,
The Cepheus Engine.
https://www.drivethrurpg.com/product/186894/Cepheus-Engine-System-Reference-Document?affiliate_id=35844