src/services/RedirectsService.php
public function findAllRedirects ($currentSiteOnly = false)
	{
		if ($currentSiteOnly)
			return RedirectRecord::find()->where(
				'[[siteId]] IS NULL OR [[siteId]] = ' .
				\Craft::$app->sites->currentSite->id
			)->orderBy('siteId asc')->all();

		return array_reduce(
			RedirectRecord::find()->all(),
			function ($a, RedirectRecord $record) {
				$a[$record->siteId ?? 'null'][] = $record;
				return $a;
			},
			array_reduce(
				\Craft::$app->sites->allSiteIds,
				function ($a, $id) {
					$a[$id] = [];
					return $a;
				},
				[]
			)
		);
	}
public function findAllRedirects ($currentSiteOnly = false)
	{
		if ($currentSiteOnly)
			return RedirectRecord::find()->where(
				'[[siteId]] IS NULL OR [[siteId]] = ' .
				\Craft::$app->sites->currentSite->id
			)->orderBy('siteId asc')->all();

		return array_reduce(
			RedirectRecord::find()->all(),
			function ($a, RedirectRecord $record) {
				$a[$record->siteId ?? 'null'][] = $record;
				return $a;
			},
			array_reduce(
				\Craft::$app->sites->allSiteIds,
				function ($a, $id) {
					$a[$id] = [];
					return $a;
				},
				[]
			)
		);
	}
Returns all the redirects

@param bool $currentSiteOnly

@return array