These files don't exist!
Yep, that's right, none of these files actually exist! There
is a small server-side module that parses the file name, and
generates the file. URLs behave like direct links to files.
So, there isn't a file called "cew_span_20131_20151_26163_5_336111.csv"
The server-side module consumes the file name, and figures out
what should be inside.
And thats it.
There's no database either. Just a series of CSV proxy-slices that represent the data.