The capability argument allows you to define the capability that a user must have in order to access the control for a field.
If left undefined it defaults to edit_theme_options.
You can set the capability in your config, as well as on individual fields.
Example:
<?php
// Only allow network admins to access options in this config
Kirki::add_config( 'my_config', [
'option_type' => 'theme_mod',
'capability' => 'manage_network_plugins'
];
// Add a simple text-field.
// This will inherit the capability from our config.
Kirki::add_field( 'my_config', [
'type' => 'text',
'settings' => 'my_setting1',
'label' => esc_html__( 'Text Control 1', 'kirki' ),
'section' => 'my_section',
'default' => esc_html__( 'This is a default value', 'kirki' ),
'priority' => 10,
] );
// Another text-field.
// This will override the capability of the config and be available to admins.
Kirki::add_field( 'my_config', [
'type' => 'text',
'settings' => 'my_setting2',
'label' => esc_html__( 'Text Control 2', 'kirki' ),
'section' => 'my_section',
'default' => esc_html__( 'This is a default value', 'kirki' ),
'priority' => 10,
'capability' => 'edit_theme_options'
] );
?>For a complete list of WordPress capabilities and what capabilities each user role has, please visit the documentation on wordpress.org.