Except I just noticed my final answer lost the colons after the months, so you’ll have to fix that. In fact, it looks completely wrong. Cut-and-scramble-and-paste error. It should have been like the preceding answer with “Dec-Feb: Sa Off” added.
That depends on what you’re using. I don’t think the standard OSM renderer does anything with it, not even validates it. Some applications may do something with it.
