Drop a manifest.json containing something like the following, and a new tab xhtml file in an empty directory, then tell chromium, chrome, or edge to load a new unpacked extension
{
"manifest_version": 3,
"name": "Blank new tab",
"version": "1.0.1",
"description": "A blank new tab page",
"chrome_url_overrides" : {
"newtab": "blank.en.xhtml"
}
}