Complex sentence: Within three months, an administrator allowing use of ECP for any purpose, not just for ArbCom and sockpuppetry: that, with community scrutiny, administrators would be allowed to use ECP protection.
Split into simpler sentences: Within three months, an administrator allowing use of ECP for any purpose, not just for ArbCom and sockpuppetry. With community scrutiny, administrators would be allowed to use ECP protection.