Ok, a fresh download works just fine. 
I’m not sure how I managed to get a broken file twice by running wget on two separate machines (connectivity issues…?), but the one I used on the root server is clearly damaged. It’s far too small, for starters.
In case you want to use it for something, I’ve put the broken file here and will leave it there for a while.
Anyway, thank you for your support and – as always – for the awesome tool! 