Hi,

librust-blosc2-rs-dev is uninstallable on all architectures, which is why
rust-blosc2-rs never migrated to testing:

  librust-blosc2-rs-dev Depends:
librust-blosc2-sys-0.4+regenerate-bindings-dev

rust-blosc2-sys 0.4.0+dfsg-1 doesn't provide that: its
debian/patches/drop-static
removes the "regenerate-bindings" feature (together with "shared" and
"static"), so it only provides the +bindgen variant.

rust-blosc2-rs's own debian/patches/drop-static removes "shared" and
"static"
but keeps

  regenerate-bindings = ["blosc2-sys/regenerate-bindings"]

so debcargo still generates the +regenerate-bindings feature package and the
dependency on the blosc2-sys feature that no longer exists.

The attached change extends rust-blosc2-rs's drop-static patch to also drop
the regenerate-bindings feature, matching blosc2-sys. debian/control then
needs
regenerating with debcargo (the librust-blosc2-rs+regenerate-bindings-dev
provides and the librust-blosc2-sys-0.4+regenerate-bindings-dev dependency
go
away). I checked the updated patch applies cleanly to the 0.4.0 upstream
source.

We hit this in Ubuntu, where the package is stuck in proposed for the same
reason.

Thanks,
Sebastien Bacher