The nix.package in configuration.nix was overriding lix itself.
nix.package
configuration.nix
lix
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BSHRYQDN3FSZZQQ3CYDG5GT24M3RXXYB5VWTOI7DTXBUL7GF5JIAC
MDC4P4ZAVIZRIWFA7SAUTI7JYJLOTB3NEB3KXPF7ZCGBKRNSUTBQC
6I2HQYU2ZU5STWSYDZV3PLK6J3J4DWKXIJEZ3CCOVPXUJRR627BAC
url = "git+https://git@git.lix.systems/lix-project/lix?ref=refs/tags/2.90-beta.1";
url = "git+https://git@git.lix.systems/lix-project/lix";
package = pkgs.nixVersions.latest;
# package = pkgs.nixVersions.latest;