This is inaccurate, yes Dragonborn come from late 3.x, but they aren't renamed Half-dragons. They come from a semi-obscure supplement called Races of the Dragon. There they are called "Dragonborn of Bahamut", but instead of a true breeding race, they are part of the trans-human races that were popular with designers by then. (They were humans who made a ritual to Bahamut and became draconic as a result)
Maybe in concept. Humanoid dragons and half dragons relate 3.0 2E had them.