It takes me a while to finish a post about Magic Mirror. It was too laborious to pull out the config file. But now I know transfer.sh site. It main functionality is “Easy file sharing from the command line” and it really was easy.
$ curl --upload-file ./config.js https://transfer.sh https://transfer.sh/EDqx8K/config.js
And this is everything.
Edit. It is not a blessed by good program. I have no idea how to delete the file. Delete link generator is not working. And the worst is that Firefox block this site as a “This website is on the list of sites with potentially dangerous content.”