Starting with the home team of the very first international football match in 1872, a county is the lineal world champion until they get beaten by another team, which in turn inherits the title.
Keep in mind, that nations competing in international football don't neccesarily need to be countries in standart Jetpunk definitions and can include former nations, which don't exist anymore today.
Quiz gets updated, when a new champion is crowned.
Source: https://www.ufwc.co.uk/