Clon maintains a search path for looking up files. Theme files are
supposed to be located in a themes directory of every
directory in the search path. By default, the search path is as follows:
~/.clon/
~/Library/Application Support/Clon/ (MacOS only)
~/share/clon/
/Library/Application Support/Clon/ (MacOS only)
/usr/local/share/clon/
/usr/share/clon/
The search path can be modified with the --clon-search-path built-in
option or its accompanying CLON_SEARCH_PATH environment variable.
It takes a list of colon-separated directories as argument. This
argument is in fact optional. Not providing an argument is equivalent to
providing an empty one, which basically reduces the search path to the
application’s current directory.