Comment 13 for bug 160131

Library is file /usr/share/emacs/22.2/lisp/erc/erc.elc

erc-version-string is a variable defined in `erc.el'.
Its value is "Version 5.2"

I can still trivially reproduce with the kill-buffer maneuvre. The obvious indication is that there is now a second buffer #onetest<2> where erc has joined #onetest on server2