Can't speak for Canada, but in the US, the jury process is a mix of black-letter law (explicit legislative acts) and administrative law (rules made by the court

Can't speak for Canada, but in the US, the jury process is a mix of black-letter law (explicit legislative acts) and administrative law (rules made by the court system under broad powers granted to it by legislation). Tradition and precedent were the inspiration for a lot of modern law, but we explicitly re-implemented most of it via legislative and/or administrative law.