---------------------------------------
file 1   Tag    Ref    Name           
---------------------------------------
        1965      2    g0             
        1965      3    g0/g1          
        1965      4    g0/g1/g1.1     
---------------------------------------
file 2   Tag    Ref    Name           
---------------------------------------
        1965      2    g0             
        1965      3    g0/g1          
        1965      4    g0/g1/g1.1     
---------------------------------------
file1     file2
---------------------------------------
    x      x    g0             
    x      x    g0/g1          
    x      x    g0/g1/g1.1     

