Amadeus GDS itinerary code - what do 050 and 010 codes mean?

Question

I have the following itinerary from Amadeus, what do the lines starting with codes 050 and 010 mean?

1  EY1998 M 18DEC 4*DUSAUH DK1  2105 0635  19DEC  E  0 332 M                  
   050 AB 7460                                                                
   OPERATED BY AIR BERLIN                                                     
   SEE RTSVC                                                                  
2  EY 204 M 19DEC 5*AUHBOM DK1  1545 2025  19DEC  E  0 320 M                  
   010 9W 6519 /AB 4092                                                       
   SEE RTSVC                                                                  
3  EY 203 L 11JAN 7*BOMAUH DK1  2140 2340  11JAN  E  0 320 M                  
   010 9W 6520 /AB 4093 /AZ 5788                                              
   SEE RTSVC                                                                  
4  EY 005 L 12JAN 1*AUHMUC DK1  0225 0615  12JAN  E  0 333 M                  
   010 9W 6362 /AB 4007 /BT 5729 /GA 9068 /HM 5026 /TP 6919 /UL               
   SEE RTSVC  

Answer 1

010 lists other flight numbers assigned to that flight (code share flights sold by other carriers). In your example you are on three flights operated by Etihad, but seats are also sold under code share agreements by Air Berlin, Alitalia, Jet Airways, etc

050 lists the actual flight number of the operating carrier, which in your example is Air Berlin. Etihad sells seats on that flight under code share agreements with their airline designator but you fly on an Air Berlin plane.