Certain Lua Versions Not Displaying

[Seeker0472]

lua5_1 can't be found by searching https://search.nixos.org/packages?channel=unstable&from=0&size=50&sort=relevance&type=packages&query=lua5_1
but lua5_3_compat can be found https://search.nixos.org/packages?channel=unstable&from=0&size=50&sort=relevance&type=packages&query=lua5_3_compat

Both are defined in here https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/interpreters/lua-5/default.nix

The same issue occurs with lua5_4,lua5_3,lua5_2,lua5_2_compat