The calendar component of Thunderbird needs to be installed as an add-on for historical reasons. https://www.mozilla.org/en-US/projects/calendar/ https://www.m

The calendar component of Thunderbird needs to be installed as an add-on for historical reasons. https://www.mozilla.org/en-US/projects/calendar/ https://www.mozilla.org/en-US/projects/calendar/ https://en.wikipedia.org/wiki/Mozilla_Sunbird https://en.wikipedia.org/wiki/Mozilla_Sunbird https://blog.mozilla.org/calendar/2006/10/sun_microsystems_announces_int/ https://blog.mozilla.org/calendar/2006/10/sun_microsystems_a...