> For the complete documentation index, see [llms.txt](https://ilogtail.gitbook.io/ilogtail-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://ilogtail.gitbook.io/ilogtail-docs/concepts/key-concepts.md).

# 关键概念