How does the positive list ("whitelist") work?

[danielmmmm]

I installed ATD in Firefox 104.0 and it seemed to work as intended, suspending inactive tabs. Since there are only few webpages that use an extreme amount of memory (>300 MB), I thought it a good idea to only suspend these particular tabs. I added "finn.no" (without the quotation marks) to "Only discard the following inactive hostnames...". And suddenly, ATD stopped suspending tabs! To be on the safe side, I also tried "re:finn.no", "re:finn", and "www.finn.no". These didn't work either. I activated "Display logs", but didn't see anything in the console. In about:config, "browser.tabs.unloadOnLowMemory" was already set to false. I also noticed that the ATD icon turned blue for some tabs, even though they weren't in the positive list. Having "finn.no" in the positive list made ATD report that e.g. youtube.com and github.com where on the "whitelist".

Did I miss something here? Did I use a wrong hostname?