PHP 7.3 reached end of support in December 2021 and Adobe Commerce 2.3.x reaches end of support in September 2022. You may want to consider planning your upgrade now to Adobe Commerce 2.4.x and PHP 7.4.x to help maintain PCI compliance.
CacheInvalidate
The CacheInvalidate module is used to invalidate the Varnish cache if it is configured. It listens for events that request the cache to be flushed or cause the cache to be invalid, then sends Varnish a purge request using cURL.