What does the last column in the MIDI Setup say?

I'm trying to configure my microphone in the Audio MIDI Setup app. When configuring a microphone, the last two columns are cut off. The 2nd-to-last column is probably Mute. What's the last column that says "Th..."? There's no way to expand the column, and there's no tooltip when you hover over it. I've also grepped the application folder, but it doesn't return a localization file or anything: grep -aiIr mute '/System/Applications/Utilities/Audio MIDI Setup.app/' Can anyone figure out what the "Th..." column does?