Note 1: It is normal that this certificate is signed by itself. This is the way certification authorities' certificates usually are.This authority is totally unofficial and is created for experimental purposes only. You should not trust it too much!
Note 2: It is theoretically possible (but highly improbable) that your connection to this server is faked, and you will receive wrong certificate. If you are paranoid about this, try to get the certificate fingerprint by other (non-electronic) means and compare it with that of the certificate downloaded from here.
Yes, load certificate into browser