Public header files change

It seems to be unlikely to me, but are the changed symbols mentioned in
git-log commit message 5f173040e324 supposed to be used other than
internally?  Snip:
   Avoid repeated name lookups during table and index DDL.   ...   to the Constraint node (FkConstraint in 8.4).
Third-partycode   calling these functions or using the Constraint node will require   updating.   ....
 

These seem to be pretty internal symbols to me, but I rather asking here.
Is there some project we know off that is using this functions (or is
there some obvious usecase for third-parties)?

Pavel