Changelog

Definitions

A file documenting all notable changes to a project, organized by version. The responsible developer's diary. 'Keep a Changelog' (keepachangelog.com) is the widely adopted format.
In plain English: A list of what changed in each version of a software project — helps users know what's new, fixed, or removed.
An underappreciated trust-building tool: a well-maintained changelog signals that a project is actively maintained, that maintainers care about backwards compatibility, and that upgrade decisions can be made with full information. No changelog = no confidence in upgrading.
Example: 'I always check the changelog before upgrading a dependency. If there isn't one, I read every commit message. If there are too many, I don't upgrade.'
Source: trust signal