Complex sentence: This system absolves ProtonMail from storing either the unencrypted data or the mailbox password and prevents them from divulging the contents of past emails but not future emails, or from decrypting the mailbox if requested, for instance, if compelled by a court order.
Split into simpler sentences: This system absolves ProtonMail from storing either the unencrypted data or the mailbox password. It also prevents them from divulging the contents of past emails but not future emails, or from decrypting the mailbox if requested, for instance, if compelled by a court order.