From https://developers.google.com/search/reference/robots_txt?hl=en https://developers.google.com/search/reference/robots_txt?hl... "An optional Unicode BOM (

From https://developers.google.com/search/reference/robots_txt?hl=en https://developers.google.com/search/reference/robots_txt?hl... "An optional Unicode BOM (byte order mark) at the beginning of the robots.txt file is ignored." At least they document it.