How to find where is error in this loggly record

can someone help me with reading the loggly records, I have problems with reading the message “undefined is not an object (evaluating ‘a.L’)” since I don’t have a.L anywhere in my code, I assume it’s rendered html or some script but I can’t to find exactly where the problem is.
I think the error was thrown by window.onerror

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i tried to find some code in the scripts i uploaded but no luck in finding it