Unfortunately the UI (taking after the game itself) is quite ugly. A web version should be more dynamic and legible, but I agree it would be nice to have a generated manual/enyclopedia for some game content. See also #1840 for an attempt at generating a PDF manual.
Yes, the gear symbol represents the time in seconds needed either for a unit to train (in the case of sheep, soldiers, workers, etc.) or for a technology to research.