In this context, it refers to the tenure of the Amazonian. Full time employees that are <5 years tenure have a badge with a blue border, those with 5-10 years tenure have an orangeish border, 10-15 have a red border, etc...
Orange/red badges are typically a big deal because it is very rare for people to last at Amazon past even 2-3 years, nevermind 5 years.