Re:
It's a Range bulge butted seattube, it came in to replace the ovalized tubing that came before it. So is of the higher quality, normally Tange Concept but other tubing groups may have used it as well.
Given it has the wheel at the back, placing it in the circa 92/93 era there would only have been traditional mech (conventional/bottom swing) as Top-Swing did not come till the XTR M950 1996 mechs came out. So why would anyone design it for such a mech that was not around ;-)
It was basically Suntour, Shimano at the time or Campag and maybe Sachs if you really tried hard.
Top-Pull mechs where around but the wheel gave you choice for the more common bottom-pull. That it it was a 1992 model frame and it'll have been design before Shimano release their top-pull to market in 1992 models.
Or it just some old tech in a later frame.