Created attachment 8923798 [details] no icon for amo prod.PNG [Affected versions]: Firefox 58.0a1 (20171030103605) [Affected platforms]: Windows 10 64-bit MacOS Sierra 10.13 Ubuntu 16.04 32-bit [Steps to reproduce]: 1.Launch Firefox with a clean profile. 2.Open a few tabs(including https://addons.mozilla.org/en-US/firefox/) 3.Go to "about:debugging#tabs". [Expected Results]: All the tabs have the corresponding icon. [Actual Results]: AMO and some other sites have placeholders as the tab icon. [Additional notes]: Screenshot is attached.