Cannot see new file name during upload

I am using this code to modify the file name before upload:

onBeforeFileAdded: (currentFile, files) => {
        const modifiedFile = {
            name: `${}__${}`,
        return modifiedFile

Using this I can see that the filenames have indeed been updated.

    onBeforeUpload: (files) => {
        console.log('updated files', files) // files here have `new-name` and empty `data`

However in the XHR request I cannot see the new names anywhere? How can I see the modified names for the files on the server?