If installing the 'wp-admin/' directory will be replaced with './'.
The $_wp_admin_css_colors global manages the Administration Screens CSS stylesheet that is loaded. The option that is set is 'admin_color' and is the color and key for the array. The value for the color key is an object with a 'url' parameter that has the URL path to the CSS file.
The query from $src parameter will be appended to the URL that is given from the $_wp_admin_css_colors array value URL.