The backup files are stored in [profile_directory]/Google Contacts/[account]/Google/ and [profile_directory]/Google Contacts/[account]/Thunderbird/. The Google directory includes backups for Google Contact and the Thunderbird directory includes backups for Thunderbird address book. By default, it stores 10 backups. If you want to change the number, create gmcont.max_backups and set it to the value by the Config Editor. If you want to disable the functionality, set it to 0.
The both backups are CSV files and they are named as account-yyyymmdd-hhmmss.csv. They can be imported by the import functionalites of Thunderbird and Gmail.
The functionality assume to use the import functionalities of Thunderbird and Gmail, the following fields cannot be restored:
- Thunderbird cards: Screen name, Prefers to receive messages formatted as, and Allow remote images in HTML mail
- Google contacts: Other fields In the More information, photo.
It is an experimental functionality. If you find problems or have suggestions, please let me know.
If you cannot import a backup file for a Thunderbird address book due to a character encoding problem, see the post and try Google Contacts v0.4.10.