For instance, I have a domain I use as a file hosting which I can link to when I want to share something (I used to use Imgur for this purpose before, but frankly I don't trust any image host at this point, so I set up nginx to host a single directory). As you need to know the file names to download them, the domain would appear to be unused.
Although now that I look at I suppose I do explain its purpose, so here is that: https://i.xfix.pw/.