In Windows, I found this link and was able to download the files. see screenshot Let me go see what happens in mac.

https://help.geogebra.org/topic/downloading-ggb-files

Also works for me on mac. see screenshot Show us what you're getting when you try.

When I download a GeoGebra file from my website https://wisbaksels.nl/downloads/ , I get the data in my browser window, in stead of getting the opportunity to save the file. Downloading a file from the geogebra.org site is OK on my iMac, too.

I have the same issue on your site. I'm not Dev, but don't think this is a browser issue. This appears to be a site design issue IMHO, but someone closer to Dev will need to chime in. Comparing the way your site code looks to the other site is interesting, but again I'm not Dev.

Chrome does handle it better, could be a browser issue. You could open a bug to get input from Dev.

Thank you for your help! I don't know how to change my site to solve this problem. I have zipped all GeoGebra files and appended this zip-file to the list of files. This way, people can always get the GeoGebra files.