nixos/home/jupyter-config/lab/user-settings/@jupyterlab/htmlviewer-extension/plugin.jupyterlab-settings

{
    "toolbar": [
        {
            "name": "refresh",
            "command": "",
            "disabled": false,
            "rank": 10
        },
        {
            "name": "trust",
            "command": "",
            "disabled": false,
            "rank": 20
        }
    ],
    "trustByDefault": false
}