How do I get the URL for a dropped image using a Chrome userscript?

A file (when you use console.log(file) to log dropped file) in chrome is like:

{
  name: "a.txt", // file name
  size: 2473, // 2kb
  type: "text/plain", // file type
  lastModified: 1613374662130, // lastModifed
  lastModifiedDate: ..., // lastModifed Date
  arrayBuffer: ... // Buffer for reading the content
}

But you don't have access to the path or fullPath of it (for security reasons).

Also you can read its content by FileReaderApi.

Not sure I understand it well, but if I do, you won't be able to have a file path (meaning the dropped file fullpath).
It's a "protection" from browsers. But you can at least get the name of it.

var file   = e.originalEvent.dataTransfer.files[0],
    reader = new FileReader();

reader.onloadend = function (event) {
    console.log(file);
    // filename is in file.name
    // ... do something here
}

reader.readAsArrayBuffer(file);

Here is a jsFiddle of how to do it: jsFiddle demo