Found it:
The Jailer has the option of imprisoning one person for a whole day and night. They will send the narrators their target before the day begins and that person will be subsequently imprisoned for the day. A person in jail cannot speak in the thread or pm anyone at all involved in the game. Any violation of this will result in a further day of imprisonment. A third violation will mean an auto-lynching for that person. The person in prison can be lynched just like anyone else during the daytime voting, but they cannot participate themselves in the voting. However, during the night time, a person in jail will not be whacked as they are behind a jail cell. The jailer may not imprison the same person twice in a row. If the jailer is killed, there will be a random draw of all regular civilians, and one of them will secretly receive the jailer role. This is the only reassigned role allowed in the game. Once the jailer has been reassigned, it will not be reassigned a third time. The Jailer can also not imprison themselves.
Nowhere in this part it's said that the special roles can't do what they are supposed to do while being jailed. I think Klin can protect tonight.