An "inherited" ArcGIS Server 10.5.1 instance on Windows, has the logging directory set to the default: C:\arcgisserver\logs\<server_name> location.
In Manager, I cranked the verbosity level up to DEBUG for a testing session on a particular web app. I shut down all the other services running on that test server except the one the web app being tested uses. Changed the IIS logging frequency from daily to hourly. Restarted both IIS and ArcGIS Server.
Had a power user test the web app for about an hour. Then stopped ArcGIS Server & IIS. In the Manager Log Viewing interface, (as expected) I see a ginormous amount of info - looks like it would easily be 100 pages (or more) to cover the entire testing time period. I have zero desire to manually scrape 100 pages of info off the "printer friendly" view and paste it into a spreadsheet, as the ESRI help docs suggest. I've opened up both the ArcGIS Server raw log files for the server, the map service, and the IIS logs in a text editor - and they contain only a tiny fraction of the info that the Manager Log Viewer GUI is displaying. I have searched every place I can think of, but I'm not seeing any other log files containing the expected DEBUG level of verbosity.
Where is this detailed log info being stored? I would like to be able to get at it directly without having to screen scrape one page at a time from manager, but I'm not finding it. Tried the ESRI Log Parser freebie - but it's not showing me the same level of detail either. What am I missing?