The ClassInfo objects describe an inheritance hierarchy, with each ClassInfo instance containing a pointer to its parent class. These links should reflect the inheritance hierarchy of C++ classes below JSObject. For the large part it does, but in some cases entries in the C++ hierarchy are skipped over. This presently likely doesn't matter, since intervening C++ classes may not have ClassInfo – but would be a potential bug were ClassInfo were to be added.
Created attachment 83195 [details] The patch
Fixed in r79240.
Attachment 83195 [details] was posted by a committer and has review+, assigning to Gavin Barraclough for commit.