User-defined colors in /etc/X11/app-defaults/XTerm

[Fergus Daly]

Thanks so much for both responses. Utterly informative and helpful.
1    Have recovered and placed default /etc/X11/app-defaults/Xterm
2    Have commented out all lines beginning "echo -n $'\e]4; .. .." in /etc/bash.bashrc 
3    Have so far not attempted any of ~/.X* or ~/X* or setting LS_COLORS
So for the first time for decades (maybe, since ever) will try defaults in all of bash, mintty, xterm and work from there.
(I might even like them.) (Probably not - many too pale .. ..)
Thanks again for long and sympathetic responses.