Mozillazine didn't parse those URLs correctly, trying again with %hh escaping.
blocking1.6+ and open (12):
http://bugzilla.mozilla.org/buglist.cgi?resolution=---&field0-0-0=flagtypes.name&type0-0-0=equals&value0-0-0=blocking1.6%2B
blocking1.6? and open (22):
http://bugzilla.mozilla.org/buglist.cgi?resolution=---&field0-0-0=flagtypes.name&type0-0-0=equals&value0-0-0=blocking1.6%3F
blocking1.6- and open (23):
http://bugzilla.mozilla.org/buglist.cgi?resolution=---&field0-0-0=flagtypes.name&type0-0-0=equals&value0-0-0=blocking1.6%2D