These are files that come with Emacs. The Emacs distribution is divided into subdirectories; e.g., etc, lisp, and src. Some of these (e.g., etc and lisp) are present both in an installed Emacs and in the sources, but some (e.g., src) are only found in the sources.
If you use Emacs, but don’t know where it is kept on your system, start
Emacs, then type C-h v data-directory RET. The directory
name displayed by this will be the full pathname of the installed
etc directory. (This full path is recorded in the Emacs variable
data-directory, and C-h v displays the value and the
documentation of a variable.)
The location of your Info directory (i.e., where Info documentation is
stored) is kept in the variable
C-h v Info-directory-list RET to see the value of this
variable, which will be a list of directory names (after Info has been
started). The last directory in that list is probably where most Info
files are stored. By default, Emacs Info documentation is placed in
For information on some of the files in the etc directory, see What informational files are available for Emacs?.