How to locate culprit for "Please correct the XML data and try again" error

Question

Getting the following error on the cart page of Magento 2, checkout_cart_index. It's a code base with no version control and this issue is present even when I'm using the default Luma theme. I've run diffs between the original version, re-updated everything with Composer, but I didn't see any core files (app code and theme) modified.

Cache file with merged layout: LAYOUT_frontend_STORE1_7e13260053f56644d576f1e487266f9a1 and handles default, checkout_cart_index: Please correct the XML data and try again. [] []

I've traced it back to...

Magento\Framework\View\Model\Layout\Merge to
Magento\Framework\View\Model\Layout\Update\Validator to
Magento\Framework\Config\Dom.

However, I still can't find the actual XML layout file with the schema violation. Is there a way to find out which file is the culprit without using an IDE like PhpStorm? (I tried a few online validators, but they did not return relevant errors)

Answer 1

Basically no, even with an IDE. On Github ( https://github.com/magento/magento2/issues/3812 ) a Magento contributer piotrekkaminski writes:

it's a problem in most cases since validation is done on already merged file that no longer references the original files. We will add paths in places where it is possible.