Copy drivers from one Armature to another of the same kind I have a mesh/armature combo, which I developed in a good amount of steps.
The first iteration has drivers for bones which drive other bones of the armature. While developing the neither the armature nor the mesh where topology-wise changed.
In the current last iteration I noticed (too late) that those drivers got
lost somewhere.
The first iteration and the current iteration are in two different files.

How can I copy/transfer those drivers from the first iteration of that armature/mesh to the current last one?

PS: I cannot provide a *.blend file. It is not my decision.
File append from the menus allows the Blender User to move an armature from one file to the other.





Now the two armatures are in the same file.  
Now you can copy and paste Python Scripts or drivers from one armature to the other.  This can be done manually or from another script.  For small amounts of copies I suggest the task be done manually, otherwise via Script.





Of course you may be able to just copy and paste the text of the driver from while file to the other.  Two Blender files can be open at once.
This proposed answer is intended to be a high level guide to complete your task.  This is not a tutorial.
We have not discussed the particulars of a simple copy of a driver from one object to the other.  The detail required to do so was not given in the original question.