XML processing error when served via file://

[Bunkerbewohner]

Using the latest master version with this configuration, serving the app from file (i.e. file://[path-to-plume]/index.hml).

{
    "owners": ["https://mag.solid.community/profile/card#me"],
    "title": "Mathias Kahl's Blog",
    "tagline": "About software development",
    "picture": "img/logo.svg",
    "fadeText": true,
    "showSources": true,
    "cacheUnit": "days",
    "defaultPath": "posts",
    "postsURL": "https://mag.solid.community/public/blog/posts/"    
}

The following error shows:

Sorry for the German; but it says: XML processing error: not well-formed address [...]/config.json, row 1, column 1.

What I found curious is the LocalStorage key that was used: null/C:/Users/mform/Code/solid-plume/index.html. The null is problem not intended. And the content is:

{"user":{},"config":{"owners":["https://mag.solid.community/profile/card#me"],"title":"Mathias Kahl's Blog","tagline":"About software development","picture":"img/logo.svg","fadeText":true,"showSources":true,"cacheUnit":"days","defaultPath":"posts/","postsURL":"https://mag.solid.community/public/blog/posts/","saveDate":1538730028086}}```

This error does not appear when I serve it through a webserver. Either way it doesn't "find a blog url", but that is another issue.