Q:

Android Chrome Beta - Splash Screens from Homescreen

My website does not show the new splash screen (https://developers.google.com/web/updates/2015/10/splashscreen) when loading from homescreen, although I linked a manifest.  Therefore I believe, I made an invalid manifest. 
Here is the index.php code: 
 <link rel="manifest" href="sharedcode/webappmanifest.json"> 

And here is the complete webappmanifest.json code:
{
  "short_name": "Igel100",
  "name": "Igel100",
  "start_url": "./?utm_source=web_app_manifest",
  "icons": [
    {
      "src": "/projekte/igel100/data/webappicon.png",
      "sizes": "512x512",
      "type": "image/png"
    },
  ],
  "background_color": "#9fa8da",
  "theme_color": "#ccccff",
  "display": "standalone",
  "orientation": "any"
}

A:

On the surface it the manifest looks ok, here are a couple of things that you can also check:

Suggest you add a 192x192 image, it is the closest to 48dp at the highest screen density (4x)
Ensure that when you added the icon to the homescreen it was done after Chrome supported splash-screen.   If you added it before we can't update the homescreen entry, thus it won't appear.  Essentially try to add to homescreen again and it should work.