Who determines the title of an initiative?

Referendum Act (amended date: 2018/01/03)

Article 9. To raise a proposal of referendum, the leading proposer shall submit the main text of the proposal, a statement of reasons, the original copy and a photocopy of the list of proposers to the competent authority unless otherwise prescribed.

There shall be only one leading proposer as referred to in the preceding Paragraph, and the main text shall be limited to 100 words and the statement of reasons 2,000 words. The part in excess of the aforesaid limit will not be publicized or published in the referendum bulletin. [...]

This issue is not clearly defined in the legislation. One can only assume that it is the proposers of the initiative who determine the title.