CIP-0009 contains upgradeable parameters, if certain keyholders sign them, they appear to be changeable without updates to node software or configuration files: https://github.com/cardano-foundation/CIPs/blob/master/CIP-0009/README.md#updatable-protocol-parameters
We just saw a change to block-size and Plutus script size in epoch 306, how was this change effected if it is not reflected in software or config files, is it an on-chain transaction? How can we discover those in an explorer?
How are Upgrade-able parameters removed? For example the decentralization flag still shows in mainnet-shelley-genesis.json, has it been removed now, and if so, how?