I was curious about this too and it’s actually a bug— these blue dots are random parks or park features. Most parks are polygons, but less than 5% or them are points from volunteer mappers who didn’t make them polygons and so these stray points seem to slip through and get plotted as the matplotlib default color…

If only I knew this before I printed it out and attached it all together with rasterbator lol

Yes, the blue and orange dots are from the water and parks Nodes and Ways in the OSM data.

It doesn't look like the orange and blue colors are part of the theme definitions, so the rendering library may be using some default values. This is why they are rendered in the same color on images using different theme files.