Based on "This can result in multiple releases a day.", I'm guessing this is a web application, so there's rarely documentation (outside of an externally managed help center, that might get outdated). No change logs. Quality - a lot of web apps rely on automated testing and user reports. If there's manual QA, it's done on the pull/merge request level or periodically on master/main/trunk. When someone is done and says "it works", it can be deployed on production, potentially passing through staging.

The above is just a hypothetical based on how I've seen a lot of web apps being done.

auto-generated e2e test reports using cypress.io + gerkhin...

for release reporting, it's (currently) quite informal and ad-hoc. Technical releases are often behind feature-flags so we can separate this from customer-facing launch comms.