Compressing compressed files

[Andreas Enge]

Hello,

I am seeing this funny command being executed on one of the build machines:
   bash -c guix archive --export 
/gnu/store/06g54r7am7ka96d7jydgmayfyqgx1s1l-cfe-3.5.2.src.tar.xz | xz -c

Would it be difficult to prevent re-compressing of already compressed
source when offloading? Especially since xz is rather expensive, and more
or less occupies one core of the arm machines.

Andreas