[+] Z.e.t.a. X

+ Z.e.t.a. X is the band name as it is used all over on the releases and within the booklets and interviews and has actually a meaning:
The booklet of Feoh explains + Z.e.t.a. X as an expression that is a synonym and abbrevation for the very long magic formula of the universe. New magic formulas can be added in front of the + and everybody is invited to add its own magic world formula to + Z.e.t.a. X or even become an imaginary member of + Z.e.t.a. X.