This means I, as a large multi-cultural humanist empire will see a variety of cultures cropping up in my colonies, rather than only my primary culture. Personally I think this is a nice change and is, in a way, immersive. The events are mechanically simple, and pick a province at random to 'clone' the culture of to the developed colonial province after it finishes developing. Through the use of a couple of events and province flags, the culture of colonial provinces is switched to a random accepted culture in your nation with weighting towards the more dominant cultures.
Dynamic colonial cultures mod is a lightweight mod that changes how cultures are assigned in colonial provinces.