Paste this into your console when you are on the redirects settings page in you Raiboxes admin. Adjust subdomain value if needed or just remove.

const redirects = JSON.stringify([...document.querySelectorAll('[id^=redirect_item_]')].map(el => {
    return {
        subdomain: 'www',
        source: el.querySelector('[name$=_source]').value,
        target: el.querySelector('[name$=_target]').value,
        type: el.querySelector('[name$=_type]').value,
        regex: el.querySelector('[name$=_regex]').value,
    }
}))

then just inspect the redirectsvariable and copy the contents. Done.