You can open the svgs diagrams here: 

https://app.diagrams.net/#Uhttps%3A%2F%2Fgitty.informatik.hs-mannheim.de%2F3029257%2FProgrammiertestat_2%2Fraw%2Fbranch%2Fmain%2FUML.svg

https://app.diagrams.net/#Uhttps%3A%2F%2Fgitty.informatik.hs-mannheim.de%2F3029257%2FProgrammiertestat_2%2Fraw%2Fbranch%2Fmain%2FVersandkostenpreis%2520Netto%2520berechnung.svg
 
Or download and open it with drawio.