The text 'Is this really my exit text?' was an example of me
just modify it.
I think, it's hard-coded in AM itself (but I'm not sure).
If you look at AM-sourcecode, there is in main.cpp the line #445 with text "Exit Attract-Mode?",.
Probably it works like this:
if language xyz123 is selected & there is no translation of a specific command,
then so use default translation of AM itself (hard-coded in AM itself).