What kind of bytecode is it in etherscan.io?

Question

I have read some contracts from etherscan.io, and here are something that I don't understand:

1. Why there are some contract addresses that do not have contract source code?

   Here is an example:https://etherscan.io/address/0x1c8d404c27d9c1705d459f351e9b609dbc9f10f9#code

2. As for the contracts that have source code on the website, the bytecode is creation bytecode, here is an example:https://etherscan.io/address/0xc3f5d1d366e73c24374f49ca7ec732ec9a42ee10#code. But I noticed that like the above example https://etherscan.io/address/0x1c8d404c27d9c1705d459f351e9b609dbc9f10f9#code, the bytecode of contracts that don't have source code on etherscan.io is not creation bytecode, by comparing to the input data in https://etherscan.io/tx/0x892211402dfb11ea162b3d7d302a866a2d1d2dae5b7ed5bcf7ddabc541c6032a (This is the transaction that creates the contract above). So is this bytecode runtime bytecode?

Answer 1

Why there are some contract addresses that do not have contract source code?

Because the source code of a deployed contract becomes available on etherscan only after its author has verified it on etherscan.