Por que meu layout customizado não funciona?

Question

Estou tentando criar um layout personalizado que eu possa usar para vários símbolos. Por enquanto, acabei de copiar o conteúdo de gr(bare) . No entanto, o layout não parece funcionar. Quando pressiono o Caps Lock, o layout fica inalterado. Para comparação, usei um layout interno no segundo slot, e a alternação funcionou conforme o esperado.

/usr/share/X11/xkb/symbols/custom_symbols:

default  partial alphanumeric_keys alternate_group
xkb_symbols "basic" {


    key <AD01> { [             semicolon,          colon ] }; // ; :
    key <AD02> { [ Greek_finalsmallsigma,    Greek_SIGMA ] }; // ς Σ
    key <AD03> { [         Greek_epsilon,  Greek_EPSILON ] }; // ε Ε
    key <AD04> { [             Greek_rho,      Greek_RHO ] }; // ρ Ρ
    key <AD05> { [             Greek_tau,      Greek_TAU ] }; // τ Τ
    key <AD06> { [         Greek_upsilon,  Greek_UPSILON ] }; // υ Υ
    key <AD07> { [           Greek_theta,    Greek_THETA ] }; // θ Θ
    key <AD08> { [            Greek_iota,     Greek_IOTA ] }; // ι Ι
    key <AD09> { [         Greek_omicron,  Greek_OMICRON ] }; // ο Ο
    key <AD10> { [              Greek_pi,       Greek_PI ] }; // π Π

    key <AC01> { [           Greek_alpha,    Greek_ALPHA ] }; // α Α
    key <AC02> { [           Greek_sigma,    Greek_SIGMA ] }; // σ Σ
    key <AC03> { [           Greek_delta,    Greek_DELTA ] }; // δ Δ
    key <AC04> { [             Greek_phi,      Greek_PHI ] }; // φ Φ
    key <AC05> { [           Greek_gamma,    Greek_GAMMA ] }; // γ Γ
    key <AC06> { [             Greek_eta,      Greek_ETA ] }; // η Η
    key <AC07> { [              Greek_xi,       Greek_XI ] }; // ξ Ξ
    key <AC08> { [           Greek_kappa,    Greek_KAPPA ] }; // κ Κ
    key <AC09> { [           Greek_lamda,    Greek_LAMDA ] }; // λ Λ
    key <AC10> { [            dead_acute, dead_diaeresis ] }; // ´ ¨

    key <AB01> { [            Greek_zeta,     Greek_ZETA ] }; // ζ Ζ
    key <AB02> { [             Greek_chi,      Greek_CHI ] }; // χ Χ
    key <AB03> { [             Greek_psi,      Greek_PSI ] }; // ψ Ψ
    key <AB04> { [           Greek_omega,    Greek_OMEGA ] }; // ω Ω
    key <AB05> { [            Greek_beta,     Greek_BETA ] }; // β Β
    key <AB06> { [              Greek_nu,       Greek_NU ] }; // ν Ν
    key <AB07> { [              Greek_mu,       Greek_MU ] }; // μ Μ

    key <LSGT> { [         guillemotleft, guillemotright ] }; // « »
};

/usr/share/X11/xorg.conf.d/10-evdev.conf:

    ...

    Section "InputClass"
            Identifier "evdev keyboard catchall"
            MatchIsKeyboard "on"
            MatchDevicePath "/dev/input/event*"
            Driver "evdev"

            Option "XkbLayout" "us,custom_symbols"
            Option "XkbOptions" "grp:caps_switch,Terminate:ctrl_alt_bksp"
    EndSection

    ...

/usr/share/X11/xkb/rules/evdev.lst:

...

! layout
  custom_symbols  Custom Symbols
  us              English (US)
...