ISE question on whats a "X_LUT3"?

Have a problem so tracing signals. What's a X_LUT3? A standard LUT3 only has an INIT value of 0 to 7. This is the "...translate.vhd" file which has this primitive and an INIT value of x"EB".

Q_n0024_0_1 : X_LUT3 generic map( INIT => X"EB" ) port map ( ADR0 => cycle(2), ADR1 => cycle(0), ADR2 => cycle(1), O => Q_n0024(0) );