Sorry, a compressed .iso is probably common, a .iso.xz is very uncommon :). We even have had some reports of people trying to copy that directly to an installation media.

Le 18 février 2021 14:56:44 GMT-05:00, Tobias Geerinckx-Rice <me@tobias.gr> a écrit :
>Julien Lepiller 写道：
>> Usually compression is provided by the webserver, but maybe ours 
>> is not configured to do that.  I think we're the only distro to 
>> provide compressed isos.
>
>Really?  Most distribution ISOs use squashfs or similar with 
>XZ/LZMA compression.  It doesn't make sense to compress that over 
>the wire.
>
>That said: XZ compression currently saves 27% (559M -> 405M). 
>Transparently serving pre-compressed ISOs with nginx (gzip level 
>9) would save about 25% (559M -> 415M), which is surprisingly 
>similar.
>
>Kind regards,
>
>T G-R