1367700 - Temporary loading same WebExtension - while archived or not - will display different icon

Status: NEW

(DevTools :: about:debugging, defect, P3)

Description

[Valentina Virlics [:vvalentina], Ecosystem QA]

Attachment: webext-screenshots.zip

Steps to reproduce:
1. Create a folder that contains a simple manifest.json and same manifest.json zipped in an .xpi archive 
2. Load about:debugging on your Firefox Release browser
3. Temporary load the webextesion first by clicking on the "manifest.json" and second by clicking on the "manifest.xpi"

Expected results:
Both cases should display the webextension in the same form.

Actual results:
Uploading the manifest.json will display a webextension with a broken icon.
Uploading the manifest.xpi will display a webextension with the default puzzle icon.

Notes/Issues:
- using latest Nightly same happens while temporary loading the manifest.json, but for the manifest.xpi the default puzzle icon is not listed at all.
Verified this on FF53.0.3(Win 7-32-bit) and FF55.0a1(2017-05-24)(Win 7-32-bit)
Attaching screenshots and used webext for this.