I don’t know what log and where that would be. Contacted the Host and they ran a file search from their tools yesterday.
This plugin/code has been on the site for over 2 years working fine. I installed the upgrade last night. Still fired off so will check w/plugin author as this addon for “excerpts” to primary plugin was purchased.
It looks like file in question is being generated by this file:
wp-content/plugins/wp-rss-excerpts-thumbnails/wp-rss-excerpts-thumbnails.php
with this line of code being responsible for it:
http://www.wprssaggregator.com
file_put_contents('C:\dump.txt', $item->get_content());