Style File: tmbook.ts

Dear TeXmacs users,
In my TeXmacs, I modified the tmbook.ts file.
It worked perfectly but I forgot to save a copy of the original tmbook.ts file.
I would like to be able to switch from the original file to the modified one.
I deleted the content of the style/book/texmacs folded and restarted TeXmacs, hoping it would reinstall the original file as it did when I installed TeXmacs the first time. To no avail!
I searched the internet to find this original file without finding it.

Can someone tell me where I can obtain this original tmbook.ts file ?
Thank you very much.
Normand Beaudoin