What is this field in my rinkeby.json network file

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Hi. I am using hardhat upgrades plugin to deploy my proxy, proxy admin and implementation contract. Afterwards, I use a script to extract the addresses of all the deployed contracts from the generated rinkeby.json file into a separate file. Under the "impls" field, I do not understand what's the first field which is a very long address b0beb24c340350c72510cfb042b4f6509cf9f8998aab5b2eb3d142006c3c8aab. Here is a screenshot of my rinkeby.json file.

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Hi @Maham_Zaidi,

That string is a version identifier used by the upgrades plugins to identify different versions of implementation contracts. It is a hash of the implementation contract's init bytecode, so any changes to the implementation contract logic would result in a different version identifier.

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Hi, out of curiosity, how is this hash computed? Which hashing function is used and what information is included in it? Is it the entire object after the identifier ?
{"address":"0x123", "txHash":"0x9876", "layout":{ "storage":[], "types":{} }}

Thanks!

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It uses a keccak256 hash of the linked bytecode without the metadata part (although it does some transformations before hashing). You can find the implementation here: https://github.com/OpenZeppelin/openzeppelin-upgrades/blob/a77c68c3362a0631b9a9a6169a44b7fe822a98f5/packages/core/src/version.ts#L15

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