Melon bread, melon buns. メロンパン。A type of kashi-pan, sweet buns or buns with sweet fillings ("kashi" means "confectionery"). An example of "Japanese-style" bread.
Melon buns are made from enriched dough covered in a thin layer of crisp cookie dough. The name comes from the fact that the top part of such round buns looks like the skin of a melon - the name has nothing to do with the taste - which is just generally sweet (that being said, there are some producers who give their melon-pan a melon flavor recently). The one below which I had on a train trip tasted buttery. The top was covered with sugar.
Other flavors also exist, and then the name "melon" may be dropped. The version with maple syrup is, for example, called "maple bread."