Hot Glue/Epoxy-like substance on DC-DC regulator
This is an eval board and is sold in an unprotected format. The components along that edge are vulnerable to fingers and errant connector plugging missions. 

I think it's just a blob of clear epoxy intended to protect the smallest and most vulnerable SMT parts from being accidentally pried off of the board. The other edges of the board are relatively protected or have larger, more sturdy parts.