Trevor does not store a copy of your database - your data stays safely and securely in your own database.
SQL is sent over the wire and only the returned results are retrieved. SQL / results are transmitted using SSL security, which protects against eavesdropping and man-in-the-middle attacks.
When you export query results from Trevor, the results are temporarily cached to improve performance and protect your database from too much traffic.
These results are cached using a version 4 cryptographically strong pseudo random UUID for 48 hours, before being automatically and permanently deleted.