Running diffoscope on .zst prints zstd progress indicators

When diffing Arch Linux packages there's some data written to stdio from the zstd process spawned by diffoscope:

1-x86_64.pkg.tar.zst : 0 MB...     
1-x86_64.pkg.tar.zst : 43 MB...     
1-x86_64.pkg.tar.zst : 126 MB...     
1-x86_64.pkg.tar.zst : 190 MB...     
1-x86_64.pkg.tar.zst : 238 MB...     
1-x86_64.pkg.tar.zst : 274 MB...     
                                                                               
/tmp/rebuilderdvJw0dy/signal-desktop-1.38.2-1-x86_64.pkg.tar.zst: 332861440 bytes 

1-x86_64.pkg.tar.zst : 0 MB...     
1-x86_64.pkg.tar.zst : 42 MB...     
1-x86_64.pkg.tar.zst : 129 MB...     
1-x86_64.pkg.tar.zst : 191 MB...     
1-x86_64.pkg.tar.zst : 239 MB...     
1-x86_64.pkg.tar.zst : 276 MB...     
                                                                               
./build/signal-desktop-1.38.2-1-x86_64.pkg.tar.zst: 332861440 bytes 
--- /tmp/rebuilderdvJw0dy/signal-desktop-1.38.2-1-x86_64.pkg.tar.zst
+++ ./build/signal-desktop-1.38.2-1-x86_64.pkg.tar.zst
├── signal-desktop-1.38.2-1-x86_64.pkg.tar
│ ├── file list
[...]

https://reproducible.archlinux.org/api/v0/builds/3162/diffoscope