set environment variable LOAD_EXTERNAL_FILES_CONFIG with JSON value sample
{
baseURL:"https://pinnacleplaza.blob.core.windows.net/assets",
// overrides saveAt
localPath:"img/icons",
files:[
{"extFile":"favicon.ico", "saveAt":""},
{"extFile":"favicon-16x16.png", "saveAt":"img/icons"},
{"extFile":"apple-icon-114x114.png", "saveAt":"img/icons"},
{"extFile":"ms-icon-144x144.png", "saveAt":"img/icons"},
{"extFile":"apple-icon-152x152.png", "saveAt":"img/icons"},
]
}