XEMACS-20.4/etc/frame-icon/ not in XEmacs-21.0

The xbm files from XEMACS-20.4/etc/frame-icon/ are not distributed with XEmacs-21.0 anymore. Of course: no default XEmacs package uses it. But the point is: my XEmacs package x-symbol http://www.fmi.uni-passau.de/~wedler/x-symbol/ uses some of them. The questions are (1) Were there copyright problems with these files? (2) If not 1, may I distribute some of them with my package? (3) If 2, who is the author/designer of these icons (to be mentioned in the "thanks" section)? Hope not to have bothered you with non-general-interest questions, - Christoph