Good catch, it would be better to use a fake stable URI:
``` 
const { id } = require('@loader/options');
let myuri = Cc["@mozilla.org/network/io-service;1"]
                    .getService(Ci.nsIIOService)
                    .newURI('addon://' + id, null, null);
```
@Mossop do you have any guess on what kind of URIs we would eventually use?
If we end up sharing same URI, we will be able to share database between the module and the addon document.
I won't say it is really important, we can also say this module has a different database.