frontend_admin.xml

<?xml version="1.0" encoding="utf-8"?>
<form>
	<fields name="params">
		<!--  Backend user account settings. -->
		<fieldset name="params" label="COM_USERS_SETTINGS_FIELDSET_LABEL">
			<field
				name="admin_style"
				type="templatestyle"
				label="COM_USERS_USER_FIELD_BACKEND_TEMPLATE_LABEL"
				description="COM_USERS_USER_FIELD_BACKEND_TEMPLATE_DESC"
				client="administrator"
				filter="uint"
				>
				<option value="">JOPTION_USE_DEFAULT</option>
			</field>

			<field
				name="admin_language"
				type="language"
				label="COM_USERS_USER_FIELD_BACKEND_LANGUAGE_LABEL"
				description="COM_USERS_USER_FIELD_BACKEND_LANGUAGE_DESC"
				client="administrator"
				filter="cmd"
				>
				<option value="">JOPTION_USE_DEFAULT</option>
			</field>

			<field 
				name="helpsite"
				type="helpsite"
				label="COM_USERS_USER_FIELD_HELPSITE_LABEL"
				description="COM_USERS_USER_FIELD_HELPSITE_DESC"
				>
				<option value="">JOPTION_USE_DEFAULT</option>
			</field>

		</fieldset>
	</fields>
</form>