Adds a little 'glow' to electric miners, assembling machines, chem plants and oil refineries, to make the factory more visible at night. Not intended as an complete replacement for lamps - think of it more like an LED display panel glowing. A brighter glow is visible when the machines are working - more like sparks flying from a whirring assembler machine.
Helps navigation through parts of the factory you might have forgotten to build lamps in :)
With 2.0 and Space Age, active buildings now glow if they have an associated tint (e.g. science packs, some chemical plant recipes, and some biochamber recipes)
