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tldr (from the acronym "too long didn't read"), is a succinct help system for CLI commands. Complimentary to man pages and "--info" documentation, it provides quick reference and can be a handy way to jog memory about basic command functionality.
There are two implementations of tldr in the GURU ebuild repository, app-text/tldr, and app-misc/tealdeer.
See the GURU guide, eselct repository and emerge for how to install.