Hi,
This would have been created, but unfortunately not added to your solution.
My guess is you have it set to create an Environment Variable when you added Datasources etc.
Now unfortunately many times these are NOT added to your solution by default, silly I know. You would have to open our solution. Select Add Existing Item, then Environment Variable. Then scroll through all the ones you see,.
Now anything with new_XXXXXXXXXX is the default prefix that is used anytime a Platform item is created. What I mean is, when you create a solution, and you add your own Published, you get a prefix. When you create things it will have THAT prefix, however the datasource creation actually uses the prefix new_ which is owned by the System/Platform.
Hence why its called that and why you need to add it. Add it, publish all customizations, export and reimport you should be good.