background/duplication.js line 1 column 1
core/script.js line 65 column 9
I am pretty confident these are not syntax errors because the code loads without any errors or problems when I load the same zip file as a temporary addon in Firefox Developer Edition?
The zip file can be accessed here: https://github.com/mozilla/addons-linter/files/3525447/duplicate-tab.zip
I created an issue on the addons linter but got no replies https://github.com/mozilla/addons-linter/issues/2758