Here one hint from Thunderbird releasenotes for version 71:
"Address books are now stored as SQLite databases. Existing address books in MAB format (using a Mork database) will be converted."
There is direct no SQLite-Driver available for LO at this time. Only connection through ODBC will work well.
LO should be able to connect to Thunderbird Address Book.
Indeed, Thunderbird 71 beta has made the switch to SQLite address book databases.
this should be an easy-hack!
the existing Thunderbird Mork driver is here:
we probably need a separate driver so users can work with both old and new Thunderbird profiles.
so perhaps best to start with copying one of the existing drivers, the result should find the address book files in a similar location like the mork driver but the data access is probably closer to one of the SQL based drivers.
"writer:file->wizards->address data source" and "base: connect to existing database" are two routes that can use the mozilla address book for testing purposes.
one advantage of SQLite should be that concurrent access from Thunderbird and LO should work better.
unfortunately i'm unable to find any documentation on how this SQLite address book is supposed to work in Thunderbird...
Thunderbird's Paul Morris kindly directed me to these reports:
[meta] remove mork usage from address book
Migrate existing Mork address books to JS provider
One more thing, the Mork removal proposal on TB developer list: http://lists.thunderbird.net/pipermail/maildev_lists.thunderbird.net/2019-August/001900.html
Even more things: the next release of TB will be 78 as the releases follow Firefox Extended Support Release cycle.
According to the FF calendar 78 will hit on 2020-06-30: https://wiki.mozilla.org/Release_Management/Calendar
TB will follow some weeks after: https://wiki.mozilla.org/Thunderbird:Home#Releases
So version 71 is not an end user -facing release. Only beta testers using LibreOffice's Mork connection will suffer breakage.