I use utf-8 in quite a lot of files (.js, .html, .css) and it works without the utf-8 BOM. (Sublime Text saves as UTF-8 without BOM by default, I think.)
At any rate, a misconfigured WebExtension should not be able to crash Firefox.
I know, but this BOM behaviour is MS Windows specific. In MS Windows you
need for any file with ut8 content (html etc) the BOM, otherwise the
chars are not displayed in the way as they should appear.
That is quite the oposite of what I was saying. I’m developing on a Windows PC and I use THML, CSS and JS files with Unicode characters in them. I just saved them with sublime and it works perfectly fine for those three file types. My files do not contain the BOM.
Firefox may behave differently for the messages.json files, though.
I’m not questioning your problem (with the messages.json). I just wanted to point out, that Firefox generally reads files as utf-8 even without the BOM.
You can use the attached files
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