What are the stipulations for being the President of the Confederation in Switzerland?

The President of the Confederation is elected from one of the seven Federal Councillors, so being a Federal Councillor is the only stipulation.

To be elected Federal Councillor, the only stipulation is that you're a Swiss citizen, but in practice, Federal Councillors are very rarely elected from a pool of random schmucks and are rather picked by members of parliament.

Swiss citizens vote for people to represent them, and MPs elect Federal Councillors.

Typically and in order to be elected into such offices in Switzerland, you have to talk two or more of the country's official languages.