Alexandro de Oliveira has a problem that I’ve also experienced. He wants to know how he can read a complete description of a package such as that given on its Elpa page. He asked on Stack Exchange and gave as an example the documentation for undo-tree. I’ve had that exact problem. I’m always forgetting some of the undo-tree keystrokes and that means I have to bring up the source to read the commentary at the front of the source file.
It turns out that there’s a much better way: as suggested by wasamasa, simply use finder-commentary to extract the commentary from the source file. That function is part of the finder package written by Eric Raymond back in 1992 so it’s been around for a long time but this is the first time I’ve heard about it.
If you’re writing a package, this tip should encourage you to spend some time on the commentary section. It can really be useful to your users, especially if the package’s UI is the least bit complicated. As usual, I’m always learning something new about Emacs.