I see, thanks for the reply.
It's not hard to convert .tsv to .cards:
1. rm -Rf ~/mnemosyne_temp && mkdir ~/mnemosyne_temp && mnemosyne -d ~/mnemosyne_temp
2. Import the .tsv.
3. Export as .cards.
Now I can restart mnemosyne with my normal, default database directory, and import the .cards file. However, this doesn't seem to overwrite the answers. When I use the deck, the answers I see are the old ones.
I can do this:
sqlite3 ~/.local/share/mnemosyne/default.db .dump
The resulting dump seems to show that both the old answers and the new answers are still in the database. It seems like when I run mnemosyne, it only finds the old answer.