Объяснить работу компонентов и шаблонов bitrix, $arParams,$arResult

<? use Bitrix\Iblock\Component\Tools;


if (!defined("B_PROLOG_INCLUDED") || B_PROLOG_INCLUDED !== true) die();


\Bitrix\Main\Loader::includeModule('iblock');


$arFilter = [
    'IBLOCK_ID' => $arParams['IBLOCK_ID'],
    'ACTIVE' => 'Y',
];


if ($arParams['SECTION_CODE']) {
    $arFilter['CODE'] = $arParams['SECTION_CODE'];
} else {
    $arFilter['ID'] = $arParams['SECTION_ID'];
}
$arResult['SECTION'] = IblockQuery::sections()
    ->filter($arFilter)
    ->sectionPageUrl($arParams['SECTION_URL'])
    ->execute()->first();


if (!$arResult['SECTION']) {
    Tools::process404(
        trim($arParams['MESSAGE_404']) ?: "Not found",
        true,
        'Y',
        'Y',
        ""
    );
}
$arResult['SECTIONS'] = [
    $arResult['SECTION']
];
$parentId = $arResult['SECTION']['IBLOCK_SECTION_ID'];
while($parentId) {
    $parent = IblockQuery::sections()
        ->filter(['ID' => $parentId])
        ->sectionPageUrl($arParams['SECTION_URL'])
        ->execute()->first();
    $parentId = $parent['IBLOCK_SECTION_ID'];
    $arResult['SECTIONS'][] = $parent;
}
$arResult['SECTIONS'] = array_reverse($arResult['SECTIONS']);
foreach ($arResult['SECTIONS'] as $parentSection) {
    $APPLICATION->AddChainItem($parentSection['NAME'], $parentSection['SECTION_PAGE_URL']);
}




$arResult['SECTION_IDS'] = [
    $arResult['SECTION']['ID'],
    pre($arResult)
];


$arResult['ITEMS'] = IblockQuery::items()
    ->filter([
        'IBLOCK_ID' => IblockService::getId('catalog'),
        'ACTIVE' => 'Y',
        'IBLOCK_SECTION_ID' => $arResult['SECTION_IDS'],
    ])
    ->select([
        'ID',
        'NAME',
        'CODE',
        'SORT',
        'DEPTH_LEVEL',
        'IBLOCK_SECTION_ID',
        'DESCRIPTION'
    ])
    ->execute()->all();


$this->IncludeComponentTemplate();