This allows easy changing of Rust versions, decoupled from Nixpkgs.
"mozilla": {
"flake": false,
"locked": {
"lastModified": 1603906276,
"narHash": "sha256-RsNPnEKd7BcogwkqhaV5kI/HuNC4flH/OQCC/4W5y/8=",
"owner": "mozilla",
"repo": "nixpkgs-mozilla",
"rev": "8c007b60731c07dd7a052cce508de3bb1ae849b4",
"type": "github"
},
"original": {
"owner": "mozilla",
"repo": "nixpkgs-mozilla",
"type": "github"
}
},