where are my old wifi passwords?

Hi, I have bought a new computer and I need to retrieve the old wifi passwords. I cannot boot the old computer, but I can see the file system. I have tried to check /etc/NetworkManager/system-connections location, indeed I do see a file that corresponds to my connection, but I do not see the password as the plain text. Instead I am getting

[802-11-wireless-security]
key-mgmt=wpa-psk
wep-key-flags=1
psk-flags=1
leap-password-flags=1

Any idea where to find the password?