These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 1.12 s (backtrack: 0/20).

[ebuild  N     ] dev-libs/jansson-2.15.1:0/4::gentoo  USE="-doc -static-libs" 478 KiB
[ebuild  N     ] dev-libs/yajl-2.1.0-r6:0/2::gentoo  83 KiB
[ebuild  N     ] app-arch/snappy-1.2.2-r1:0/1.1::gentoo  USE="-test" CPU_FLAGS_X86="avx avx2" 1083 KiB
[ebuild  N     ] app-arch/lz4-1.10.0-r1:0/1.10.0-meson::gentoo  USE="-static-libs -test" 379 KiB
[ebuild  N     ] dev-libs/avro-c-1.12.0-r1::gentoo  214 KiB
[ebuild  N     ] dev-libs/librdkafka-2.12.1:0/1::gentoo  USE="lz4 ssl zstd -sasl -static-libs" 4759 KiB
[ebuild  N     ] dev-libs/libserdes-5.4.0-r2::gentoo  61 KiB
[ebuild  N     ] net-misc/kafkacat-1.7.1::gentoo  USE="avro json" 140 KiB

Total: 8 packages (8 new), Size of downloads: 7194 KiB