This is what a useragent object looks like for a Firefox browser on a Linux OS:

{
    family: "Firefox",
    major: "110",
    minor: "0",
    patch: "0",
    source: "Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/110.0",
    device: {
        family: "Other",
        major: "0",
        minor: "0",
        patch: "0"
    },
    os: {
        family: "Linux",
        major: "0",
        minor: "0",
        patch: "0"
    }
}