These files are a modified shapefile for the Swiss cantons. The original shapefile is from GADM (http://gadm.org/), which is "freely available for academic use and other non-commercial use".
The modifications are to fix cantonal boundaries that extended beyond the national boundary, especially with regard to lakes.
See http://druedin.com/2015/11/21/a-modified-shapefile-for-plotting-swiss-cantons/ for more details.