@vstinner
If this repository would not be a proper place to store files under tool/data
Is it okay to create a new repository for this? (it's too huge)
But files need to be stored somewhere in our manageable place since
these files can be broken and loose when the times are passed.
(e.ghttp://www.info.gov.hk/digital21/eng/hkscs/download/big5-iso.txt is broken now.)

@methane@serhiy-storchaka
Also, Can you please take look at this PR?

I don't have time to understand the script. I only confirmed that this pull request doesn't change the mapping header files.

@methane
Thank you Naoki San!
The main objective of this PR is generating the same mapping header files :)
For example, we can make some change with this script when
something needs to change about supporting Japanese.
(I don't know the practical case)

@vstinner Can we merge this PR?

@corona10: I let you decide if you are confident enough to merge this PR with no review.

Since this script is not run by any CI and only run manually, I don't see any risk of regression.

It seems like "Unicode experts" (including me) don't have the bandwidth to review your change.