[Plugin: Better Related Posts] Log.txt

I have a really simple question – I want to understand the inner workings of the plugin better, enabled logging, but can’t find log.txt as suggested in the code; there isn’t error message (permission issue) associated with this in regular server log either. What else do I need to do in addition to enable logging via the plugin’s admin page? Thanks!

https://www.ads-software.com/extend/plugins/better-related/