well it depends on the part of the world where you are. In Canada, déjeuner is breakfast, diner is lunch and souper is dinner
Yes, and that is more than just a French thing. It has rubbed off on the entire east coast.
If you used "déjeuner" as a verb you can use it as lunch or breakfast. If you use "déjeuner" as a noun it is lunch. "petit-déjeuner" is the noun for breakfast.
It seems to me that they wanted to make it a proper standalone sentence, which "My breakfast." is not.
It's no less a proper standalone sentence with the period; it's just less emphatic.
When you scroll over "petit-dejeuner" it says "have breakfast".....is that because of the exclamation? are they thinking of it as a command?
Petit-déjeuner is a noun and thus can be used in an exclamation in the form that juancamilog offers. It is also a verb and therefore can be used to mean have breakfast. Without any modifiers and standing by itself it should be taken as a verb, as is also the case with déjeuner.