Verify Firefox Support

[DrewML]

This issue is a:

• Bug
• Feature suggestion
• Documentation issue
• Other (Please Specify)

Environment

Question	Answer
Magento version	N/A
Browser + version	N/A
node.js version (node -v)	N/A
npm version (npm -v)	N/A

Description

Should check whether or not this extension is compatible with Firefox's support of the WebExtensions API.

https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/Porting_a_Google_Chrome_extension

Expected result:

Either confirmation of compat with FF, or a list of issues to be resolved.