UPS-friendly 1x1 loaders.
Mods introducing new content into the game.
Augmented or new ways of transporting materials - belts, inserters, pipes!
see https://github.com/hgschmie/factorio-miniloader-redux/issues/7 (don't have a GitHub-account)
probably because https://github.com/hgschmie/factorio-miniloader-redux/blob/0a6ab0890d173fb22d1a74ee56971edc583d977b/prototypes/functions.lua#L224
there's no underground belt prefixed "stack" in the base game, only those of the 3 tiers of belt undergrounds resp. the 4 tiers (3 plus "turbo") of space age...
Fixed in 0.6.3. I will test with space age in the future. :-)
