Here is an example of the warning which is output to the console during tool execution.

/usr/local/bin/icebox_vlog:238: SyntaxWarning: invalid escape sequence '\d'
match1 = re_match_cached("IOB_(\d+)", entry[1])

These warnings are present in the following files.

icebox.py
icebox_colbuf.py
icebox_hlc2asc.py
icebox_maps.py
icebox_stat.py
icebox_vlog.py