[tromp]

> You can literally validate the entire chain with a simple python script.

I challenge you to present a "simple python script" that implements the exact bitcoin consensus rules (as codified in bitcoin core). Bitcoin is not all that simple and there's a nontrivial amount of complexity in bitcoin script alone [1].

> The chain is validated in its entirety upon first sync. 100% from genesis to tip.

The default behavior is to skip signature verification for all signatures before some relatively recent block [2].

[1] https://github.com/bitcoin/bitcoin/blob/master/src/script/in...

[2] https://github.com/bitcoin/bitcoin/pull/9484

[Kranar]

You're misunderstanding the default behavior which is fine becaue it's commonly misunderstood and discussed. At any rate signature verification is not skipped by default, what assumevalid skips is script verification. Everything else including UXTO, proof of work, the transactions themselves, are validated.

[dlubarov]

That seems a bit pedantic; the client itself prints

> Assuming ancestors of block %s have valid signatures.

when using -assumevalid. I agree it's imprecise, but it's not exactly wrong, since skipping scripts implies skipping signatures.