… since that is how it is stored in the log table.
Otherwise referrer name's that are not all lowercase will result in new visits being created:
- upper case referrer url is passed to tracker, tracker saves it as lowercase
- upper case referrer url is passed again, tracker compares lowercased w/ uppercased, fails
- tracker sets referrer keyword to host https://github.com/matomo-org/matomo/blob/3.x-dev/plugins/Referrers/Columns/Base.php#L444
- referrer keyword will be different than before, new visit is created