-  /* $OpenBSD: authfd.c,v 1.113 2018/12/27 23:02:11 djm Exp $ */ 
   +  /* $OpenBSD: authfd.c,v 1.114 2019/06/21 04:21:04 djm Exp $ */ 

what weird tool/infrastructure do these guys use, that they maintain CVS/SVN string identifiers in the files but nevertheless use git?

I actually liked these identifiers. There were tools like ident (http://manpages.org/ident/1) to deal with them.