My interpretation was that there are no KOM or points available for the L’Etape days, although there are results, so they omit the special colors to avoid confusion, while for the discovery rides there’s nothing (they’re not technically competitive events, although my legs couldn’t tell the difference in the two I’ve done so far!): you’re riding the pro route so things are the same as they are for the pro races.
But maybe I over-thought it.