About ${index} (message index number)

[DDenis-D]

Hello,
thanks for your effort for this (very useful) Thunderbird add-on.
I have some questions.
I'm figuring out a semi-manual procedure to find duplicate e-mails, which involves using Import Export Tools to export e-mails to files, and using the filename to find duplicate e-mails.
Now, I see in documentation that one of the options to compose file name is ${index}, named "message index number".
The questions are, is this a number which identifies a single mail uniquely? And: is this statically contained into the message? or is it dinamically assigned by your add-on?
If I copy/move (with standard Thunderbird copy/move functionality) from a mail folder to another, does the index number remain the same?
You get it, according the the answers, I will decide to use "message index number" for my purpose, or not.

Thanks in advance,
Denis

[cleidigh]

@DDenis-D
Thanks for the kudos!

The message index is a Thunderbird identifier that is unique per folder and not guaranteed to be either persistent or globally unique. Not useful for detecting duplicates.

In my rewrite I am working on I will add the message id which is kind of as close to unique as you can get, but very long for filenames.
If you are using Thunderbird v142- The remove duplicates addon might work for you.
https://addons.thunderbird.net/en-US/thunderbird/addon/removedupes/?src=hp-dl-mostpopular

@cleidigh

[DDenis-D]

@cleidigh, many thanks for your answer.
I've already install that add-on, but I'd like to have a procedure to - somehow - validate the decision of that add-on...
It makes me feel a bit uncomfortable the fact that I don't have control on its decisions...
Best regards.