devtools-diff
Easily diff the styles being applied to any pair of DOM elements.
Additional files are visible only to premium users
manifest.json
{
"update_url": "https://clients2.google.com/service/update2/crx",
"name": "devtools-diff",
"version": "0.1",
"manifest_version": 2,
"description": "Easily diff the styles being applied to any pair of DOM elements.",
"devtools_page": "difftools.html"
}