Understanding deployment and upgrade logs

Can someone help me find the resources to really understand Windows upgrade logs? What I find on Technet starts off pretty good, with an explanation of error codes and "some" https://docs.microsoft.com/en-us/windows/deployment/upgrade/resolution-procedures#0x800xxxxx , but in the end it's not detailed enough to do error-digging.

I am looking for an error code like

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0x80070005-0x5000F

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0x8 is a Win32 error

7 is the device

0005 is Access denied

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0x5 is SP_EXECUTION_UNINSTALL

0F is SP_EXECUTION_OP_ADD_UNATTEND

Especially that last part: what is it about? And what are these procedures below trying to access? Boot sector?

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