An announcement on the JAVAD GNSS website states “On December 21, 2012, we have tracked E6 B/C signal from all launched Galileo satellites, using TRE-G3T-E E6-band capable receiver.
“The following graphs shows SNR and ‘code-minus-phase’ combination of svn #11 (sat #81 on graph), svn #12 (sat #82) , svn #19 (sat #89) and svn #20 (sat #90). C/A stands for E1, P2 for E5B, CL2 for E6, L5 for E5A.”
The announcement includes a link to a short article describing how these codes were found. The Galileo E6 codes have not been published by the European Space Agency.