CI/CD practices play a significant role during collaborative software development by automating time-consuming and repetitive tasks such as testing, building, quality checking, dependency and security management. GitHub Actions, the CI/CD tool integrated into GitHub, allows repository maintainers to automate development workflows. We conducted a mixed methods analysis of GitHub Actions workflow changes over time. Through a preliminary qualitative analysis of 439 modified workflow files we identified seven types of conceptual changes to workflows. Next, we performed a quantitative analysis over 49K+ GitHub repositories totaling 267K+ workflow change histories and 3.4M+ workflow file versions from November 2019 to August 2025. This analysis revealed that repositories contain a median of three workflow files, and 7.3% of all workflow files are being changed every week. The changes made to workflows tend to be small, with about three-quarters containing only a single change. The large majority of the observed changes have to do with task configuration and task specification in workflow jobs. We did not find any conclusive evidence of the effect of LLM coding tools or other major technological changes on workflow creation and workflow maintenance frequency. Our findings highlight the need for improved tooling to support fine-grained maintenance tasks, such as a broader adoption of dependency management and AI-based support for ensuring and sustaining workflow security and quality.

翻译：持续集成/持续交付（CI/CD）实践在协作软件开发中发挥着重要作用，通过自动化测试、构建、质量检查、依赖项与安全管理等耗时且重复的任务来实现。GitHub Actions作为集成于GitHub的CI/CD工具，允许仓库维护者自动化开发工作流。我们对GitHub Actions工作流随时间的变化进行了混合方法分析。通过对439个已修改工作流文件的初步定性分析，我们识别出七种工作流概念变更类型。随后，我们对2019年11月至2025年8月期间超过4.9万个GitHub仓库进行了定量分析，总计涵盖超过26.7万条工作流变更历史和超过340万个工作流文件版本。分析表明：仓库中位数包含三个工作流文件，每周有7.3%的工作流文件发生变更；工作流变更通常规模较小，约四分之三的变更仅包含单处修改；绝大多数观察到的变更涉及工作流作业中的任务配置与任务规范。我们未发现LLM编码工具或其他重大技术变革对工作流创建与维护频率产生影响的决定性证据。研究结果强调需要改进工具以支持细粒度维护任务，例如更广泛地采用依赖项管理及基于人工智能的技术，以确保和维持工作流的安全性与质量。