We can extract certain information about commands.
t if symbol is a command name.
Return the documentation for the command name. It returns the first documentation found by looking at (in order): the documentation property of the command; the doc file entry associated with the doc key property; or the documentation for the function with the same name.
Return the specification, type or class (respectively) of the named command.
Returns the list of commands. Each element is the symbol of a command name, and they’re sorted alphabetically.
The optional argument type is for internal use. when it’s non-nil,
(command-name #:type type-param) is returned for commands with
“type”, instead of a symbol.
If the optional argument all is nil, returns commands only user
wants, i.e. those specified by
included. Else, all commands are returned.