The .30 Government produced in 1906 - hence the .30-06 cartridge designation. It was produced by Springfield Armory - hence the .30-06 Springfield.
This cartridge has been "modified" to the .30-06 Gibbs, .30-06 Ackley Imporved, etc. BUT, if you have a factory '06, it's a .30-06 Springfield. Some cartridges are just so predominant that you don't always hear the originator refered to i.e. the .308, .270, .30-06... It's really a .308 Winchester, .270 Winchester, .22-250 Remington...