params: explain EIP150Hash (#15237)

params/config.go

@@ -99,17 +99,18 @@ type ChainConfig struct {
 	ChainId *big.Int `json:"chainId"` // Chain id identifies the current chain and is used for replay protection
 
 	HomesteadBlock *big.Int `json:"homesteadBlock,omitempty"` // Homestead switch block (nil = no fork, 0 = already homestead)
+
 	DAOForkBlock   *big.Int `json:"daoForkBlock,omitempty"`   // TheDAO hard-fork switch block (nil = no fork)
 	DAOForkSupport bool     `json:"daoForkSupport,omitempty"` // Whether the nodes supports or opposes the DAO hard-fork
 
 	// EIP150 implements the Gas price changes (https://github.com/ethereum/EIPs/issues/150)
 	EIP150Block *big.Int    `json:"eip150Block,omitempty"` // EIP150 HF block (nil = no fork)
-	EIP150Hash  common.Hash `json:"eip150Hash,omitempty"`  // EIP150 HF hash (fast sync aid)
+	EIP150Hash  common.Hash `json:"eip150Hash,omitempty"`  // EIP150 HF hash (needed for header only clients as only gas pricing changed)
 
 	EIP155Block *big.Int `json:"eip155Block,omitempty"` // EIP155 HF block
 	EIP158Block *big.Int `json:"eip158Block,omitempty"` // EIP158 HF block
 
-	ByzantiumBlock *big.Int `json:"byzantiumBlock,omitempty"` // Byzantium switch block (nil = no fork, 0 = alraedy on homestead)
+	ByzantiumBlock *big.Int `json:"byzantiumBlock,omitempty"` // Byzantium switch block (nil = no fork, 0 = already on byzantium)
 
 	// Various consensus engines
 	Ethash *EthashConfig `json:"ethash,omitempty"`