topic Contributing to Thunderbird holiday calendars? in Discussions

Contributing to Thunderbird holiday calendars?

km55 — Tue, 14 Apr 2026 21:05:06 GMT

Hello everyone,

Hopefully I'm asking this in the correct place.

I imported the Thunderbird holiday calendar (https://www.thunderbird.net/en-US/calendar/holidays/) for Finland and noticed the, frankly, horrible localization. The translations for international holidays were absolutely terrible (seriously, even modern machine translation could do better!) and local holidays were even missing. However, I couldn't dig up any place to contribute to the translations or the calendars in general.

So, how are the holiday calendars maintained and where could I contribute?

Re: Contributing to Thunderbird holiday calendars?

wsm — Mon, 20 Apr 2026 16:45:49 GMT

Hi km55. Thanks for you strong interest in improving Thunderbird calendars. I see you have also posted at https://discourse.mozilla.org/t/contributing-to-thunderbird-holiday-calendars/147959, so I will post the same information in both places for wider visibility.

Calendar issues are tracked in github, and the current list of open issues is https://github.com/thunderbird/thunderbird-website/issues?q=is%3Aissue%20state%3Aopen%20calendar

I believe the localization aspect of your concern is covered by https://github.com/thunderbird/thunderbird-website/issues/503 to address issues about Calendarific. What do you think?

We exclusively use information from calendarific and their date quality is not high. So there is an effort in use free software to generate public calendars #753 to replace calendarific. The latest is this draft PR.

Please join and add your expertise to the project.

Re: Contributing to Thunderbird holiday calendars?

wsm — Mon, 20 Apr 2026 17:59:22 GMT

@km55 is https://github.com/janbrasna/thunderbird-website/blob/83ad6ea/media/caldata/autogen/FinlandHolidays.ics an improvement?