The full story:
There is an Irish restaurant chain called Supermacs that has opnened around 100 stores in Ireland since 1978.
Recently, McDonald’s decided that this small restaurant chain that hasn’t even made it out of Ireland needed to be taught a lesson, and sued them on the basis that “Supermacs” infringes on the “Big Mac” brand name. Which is, of course, absolutely ridiculous.
McDonald’s ended up losing the case, because of course they did, they didn’t have a case to begin with. As a result, McDonald’s lost the rights to the term “Big Mac” across the entire European Union.
Which is why Burger King gets to do this with no legal repercussions.