Rated 2 out of 5 stars

1) Are there any English localization?
2) What it do: only count number of "Re"?

This review is for a previous version of the add-on (1.0). 

Thank you for your review

> Are there any English localization?
There is no English localization yet, since I just started to create add-ons for Thunderbird. I'll make it later.

> What it do: only count number of "Re"?
When you push the button and select the popup, this add-on count number of "Re", remove all duplicate "Re" and put "Re(number): SUBJECT" in the subject box.
Like this:
(Function B)
<Re: Re: Hello> → <Re2: Hello>
<Re: Re2: Hello> → <Re3: Hello>
<Re: RE: Hello> → <Re2: Hello>
(Function A)
<Re: Re2: Hello> → <Re4: Hello>