The first two teams in the second Bundesliga are promoted to the first Bundesliga and the third team plays two relegation matches against the third-last team in the Bundesliga.
Interesting, with four teams getting promoted you have a nice variation every season.
The format of the championship is different from here, but there is undoubtedly a lot of excitement as there is still a direct clash with the third and penultimate teams in the Bundesliga.