What is “Opcodes view” at etherscan?

Question

Studying the etherscan platform and some contracts,

-->> accounts >> contract accounts >> selecting one contract,

under Contract Code there is an option to switch between Bytecodes View and Opcodes View.

What exactly is Opcodes View here and what does it represent?

There are some keywords like PUSH1, MSTORE, MLOAD, DUP1, GAS, SUB and CALLCODE in this view that repeat frequently.

What are these and what do they do?

Answer 1

Opcodes are the individual instructions that the Ethereum Virtual Machine (EVM) understands. You're looking at the equivalent of X86 assembly language, but for the EVM instead of your computer.