Damon Lipparelli <lipp(a)primus.com> writes in xemacs-beta(a)xemacs.org:
 What is the tag for the 21.1 release?  I tried release-21-1, but no
joy. 
It is the default branch.  Don't use a tag.  Stable branches are
default.  Experimental branches require a tag.  A `cvs update' from a
21.0.67 source tree should work fine.