Document real offline mode

[philippe-granet]

For security reasons, we don't have access to Internet on our server where run Renovate bot.
I achieve running OSV scanning with Renovate using this procedure:

export RENOVATE_OSV_VULNERABILITY_ALERTS="true"
export OSV_OFFLINE_ROOT_DIR="/tmp"
export OSV_OFFLINE_DISABLE_DOWNLOAD="true"
curl https://<internal proxy>/osv-offline.zip -o ${OSV_OFFLINE_ROOT_DIR}/osv-offline.zip
unzip ${OSV_OFFLINE_ROOT_DIR}/osv-offline.zip -d ${OSV_OFFLINE_ROOT_DIR}
renovate

I found no documentation about this. Is there an other procedure?