Provide data structure in another file format (and rename file extension)

Currently, the data structure is provided as 2 files if you download a dataset.
- html
- txt (but json inside)

I would suggest to:
- [x] rename the file extension "txt" to "json"
- [x] provide another txt-file with a delimiter-separated (;) data structure (as shown in the HTML file)

Especially the 2nd request would be very helpful for users who want to re-use a data structure.