Depending on the time period ....
M8 - ZG76 (Zerstörergeschwader 76) (1939 - 1941), later II./ZG76 (1943-45)
IMHO .... M8+ZE = ZG 76 + Z - the individual letter of an aircrfat ... E - IV Gruppe. The marking indicates the Stab plane of the IV Gruppe. The letter should be of green at the case. So the unit should be Stab IV./ZG76 and the marking M8+ZE.