The apparent solder blob is a PCB design issue. There is actually a piece of top-layer trace there, probably too small to be covered by soldermask. So of course it collects an actual blob of solder. The trace is actually a function of EAGLE's polygon fill algorithm. It's not explicitly drawn, but is filled in as part of the top-layer ground plane (though exactly why it takes this exact form is a bit mysterious.)
An interesting example of how a PCB design can be correct and work fine, but LOOK wrong. The Freeduino PCB was considerably worse in v1.16; it had those smt pads welded together as a solid double-wide thing. That seems to have been fixed as a result of feedback from "manufacturing" in the 1.18 version (the first production version was 1.19, I think)