There should not be dead keys in de(nodeadkeys)

[xorg/xkeyboard-config] / compat / pc

default partial xkb_compatibility "pc"  {

    // Sets the "Alt" virtual modifier

    virtual_modifiers   Alt;

    setMods.clearLocks= True;
    interpret Alt_L+Any     { 
        virtualModifier= Alt;
        action = SetMods(modifiers=modMapMods);
    };

    interpret Alt_R+Any {
        virtualModifier= Alt;
        action = SetMods(modifiers=modMapMods);
    };
};