UnexpectedTemplateFieldNameValueException
Magento\Email\Model\Template\Config\UnexpectedTemplateFieldNameValueException
What it does
This is a custom exception class that is thrown when an email template configuration contains an unexpected field name value.
Developers would catch or throw this exception when validating email template field names to ensure they meet expected criteria.
The class customizes the exception output by simplifying the stack trace for cleaner error reporting.