This was a patch so that IE10 would pass its test. It turns out named functions in IE10 look like "[Function: matcher ]" vs normal browsers with "[Function: matcher]".

This can be seen on https://ci.testling.com/twolfson/chai under d753a4a15de612dbf86d59a7f5126e897e59eec2 -> IE10 -> `not ok 80 expect satisfy`