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-default-directory-list <RET> to see the value of
this variable, which will be a list of directory names. The last
directory in that list is probably where most Info files are stored. By
default, Emacs Info documentation is placed in /usr/local/share/info.
For information on some of the files in the etc directory, see Informational files for Emacs.