mgarrett@chiark:~$ file /lib/libc.so.4.6.27 
  /lib/libc.so.4.6.27: Linux/i386 demand-paged executable (QMAGIC), stripped
  mgarrett@chiark:~$ dpkg -S /lib/libc.so.4.6.27 
  libc4:i386: /lib/libc.so.4.6.27

Unfortunately the installed kernel has no support for a.out binaries, so nothing can actually run against it any more :(