Licensing missing

Thank you.

I understand it is GPL3+ but that is not enough to comply with licensing. It requires the file with the license and program requires short preamble, please see C-h C-c in Emacs and search for "How to Apply These Terms to Your New Programs"

Check the repository root for the license file and inspect the C and Emacs Lisp source relevant to the program. Read the GNU guidance referenced in the issue, then confirm that the required license text and short preamble are present where applicable.

索引モデルが issue の本文から書いたものです。