CommonMark
CommonMark is a strongly specified, highly compatible implementation of Markdown—a lightweight markup language for creating formatted text using a plain-text editor. It aims to standardize the syntax of Markdown by providing a formal specification and reference implementations to eliminate ambiguities and inconsistencies found in earlier Markdown variants. This ensures that Markdown documents render consistently across different platforms and tools.
Developers should learn CommonMark when working with documentation, README files, or any text-based content that requires consistent formatting across multiple systems, such as GitHub, GitLab, or static site generators. It is particularly useful for ensuring interoperability and reducing parsing errors in collaborative projects where Markdown is used for writing and sharing content.