I don't know exactly what is the pipeline to copy bones to another project, so what I tried was to import a project into another project, so I had 2 skeleton and tried to drag the bones I wanted and dropped to the other skeleton, it worked, but the constraints was deleted.
There is any way to make it work?
Another thing is, when I try to add a new bone to the same Transform Constraint I click on the "pencil edit buttom" and all bones that already on that constraint is deleted so I need to reselect all bones, I can't simple add a new bone.