here https://portableapps.com/de/support/thunderbird_portable#encryption you can read
Ihre lokalen Profile von Thunderbird sind üblicherweise im Verzeichnis C:\Documents and Settings\[user]\Application Data\Thunderbird\Profiles\default.???\ installiert.
and that is wrong, it must be C:\Users\Name\AppData\Roaming\Thunderbird\Profiles
I thing this mistake will be in all languages
That description is just older for Windows 2000/XP. Your description is for Vista and later. Technically, we need both. I'll likely be removing most of these German support files as they haven't been maintained in years.
Sometimes, the impossible can become possible, if you're awesome!