I have looked at the Marketo documentation and API documentation and cannot find where I can find the details behind these emails. Like: origin of the request, what the request was, full details of the error etc.
You can find the reasons behind these error codes here on the Error Codes documentation page. AFAIK, Marketo UI does not yet show error logs or which API user/service ran into the web services error. There's an open idea about it here if you'd like to upvote it. Also, you could reach out to the Marketo support team to get additional information regarding the web services error.
Typically, more details on the error will be provided in the response that is sent to the platform making the API request. If you want to know more details about the error and the record(s) it relates to, that would be the place to look. Marketo Support can also provide you more details, but not as much as the actual response Marketo sends to the call.