Overlap_left and Overlap_right are not "magic" tags, in the sense that the
acedb code itself does not know about them. There is some code outside acedb,
in the form of the perl script that I mailed to the newsgroup and a C program
of Jean's (mieg at crbm.cnrs-mop.fr) called fixsuperlink that both use them.
In my models the Int is only attached to Overlap_right and not to Overlap_left
so as to avoid possible conflicts if the two values differed. In AcePerl
notation, the value of the integer following the Overlap_left sequence name
would be x->Overlap_left->Overlap_right(2).