@micahflee conveniently excludes how Signal Desktop left the database encryption key just sitting there in plaintext and all attachments were unencrypted for about 10 years so anyone who could get access to your Signal Desktop, which likely was installed on an OS without full disk encryption, could read all your messages. Likely how many legal investigations acquired access to Signal chats.
@abartlet@micahflee it shouldn't have existed, period. Require an HSM / Secure Enclave like the phones have as a prerequisite. They knowingly reduced the security posture of their users and didn't tell anyone.