I did some digging and discovered that burning_torch was around for over a year before it appeared in the Medieval Update, and that some people incorrectly thought it was used in Egypt. So... where did it come from? Was it just an effect that came with the game but was never used for anything? To this day, I don't think any official maps use it. Similar question about candle_light1, which didn't seem to get any use until Mann Manor even though there was a candle_light2 in Harvest Event.