5% chance to get Freelancer Reset token from Freelancer mission
10% chance to get Damged Freelancer Recall Beacon from Freelancer mission
20% chance to get one of the three ICC Drones from 'Civil Disobedience' mission
This matches my experience with these missions.
And AFAIK there is no way to decode the 4 letter spawn codes other than guessing or experimental evidence. It's easy sometimes when they correspond to just one item - but often they match a class of items (eg. like db operative armor parts + mother nitrogena).