Under "Limit selection by language" there is only "German, Swiss", so once you pick that there is no German layout as shown available anymore.
Only if you do not use the first filter-option and go directly to the next dropdown "Layout", there is a proper German layout available.
Sidenote:
As can be seen in the screenshot, having installed the system with language "German" there shows up an empty row above (english?).
Under "Limit selection by language" there is only "German, Swiss", so once you pick that there is no German layout as shown available anymore. Only if you do not use the first filter-option and go directly to the next dropdown "Layout", there is a proper German layout available.
Sidenote: As can be seen in the screenshot, having installed the system with language "German" there shows up an empty row above (english?).