He was researching his Nazi relatives. Looks like he’s going all Master Race in the first panel, but the former CO doesn’t want to actually say, “Totten was calling a fellow soldier an untermensch.”
Didn’t Flattop introduce Mabuse as another alias a few days ago? (I’m not up enough on Tracy lore to know of Dr. Mabuse is as fictional in their reality as in ours, or if he was a real person a century ago in Tracy’s world.)
(On a PC, windows-period will bring up a special characters menu, the details of which depend on exactly what flavor of Windows you have installed, but umlaut characters should be available.)
He’s dating Fluttershy now.