Chrome App/extension to remove a page element?

Yes, absolutely, that's possible and pretty easy to do: all you need is a content script that will be injected into that particular page to remove the element for you.

To do what you want you'll need to:

  1. Create a simple empty Chrome Extension (see here for the official guide) with a manifest.json file.
  2. Specify the "content_scripts" field in the manifest.json, and declare the script you want to inject. Something like this:

    "content_scripts": [
            "matches": [""],
            "js": ["/content_script.js"]

    Take a look here to find out how content scripts work.

  3. Create a content_script.js, which will delete the element for you. This script will basically only contain the following two lines:

    var element = document.querySelector('div.feedmain');