Finding details on errors from paginated report subscription runs in PBIRS

Posting this in case it's helpful to others.

I have a paginated report in PBIRS, and I have a data-driven subscription on that report.  When the subscription ran, I got "Done: 5 processed of 5 total; 5 errors."

I could find details on these 5 errors.  I looked in C:\Program Files\Microsoft Power BI Report Server\PBIRS\LogFiles and sorted by Date modified descending.  I looked in the RSPowerBI_*, RSPortal_*, RSHostingService_*, and RSOffice_* files because those were up top.  I eventually found my errors in ReportingServicesService_* which had a date modified *before* the subscription ran, but the log had the errors I was looking for.  I suppose the log file had not been flushed until I attempted to open it, thus the date modified had not changed.

C:\Program Files\Microsoft Power BI Report Server\PBIRS\LogFiles\ReportingServicesService_[date].txt is the file that contains your subscription errors.