In order to fix the recent brokenness of Thunderbird’s displayed time you need to run as root the following commands:
# copy en_DK to en_SE sudo ln -s /usr/share/i18n/locales/en_DK /usr/share/i18n/locales/en_SE echo 'en_SE.UTF-8 UTF-8' | sudo tee -a /etc/locale.gen sudo locale-gen # use new locale echo 'LC_TIME=en_SE.UTF-8' >> /etc/default/locale
optionally (once Thunderbird is fixed the setting shown below should suffice):
Go to Thunderbird’s advanced options Edit -> Preferences -> Advanced -> Config Editor and add a new key intl.locale.requested with string value en-SE