It means that the Holy See has the competence to establish personal prelatures (through an apostolic constitution) and, at the same time, establish and promulgate the statutes of the prelature erected (canon 295, Code of Canon Law).

Unlike in other entities, the statutes of personal prelatures are established and promulgated by virtue of legislative power (the Church’s power to give norms of the highest level), as indicated by the Code of Canon Law of the Latin Church (canon 94 § 3). In this case, the statutes are properly considered laws and their drafting necessarily involves the authority that promulgates them (the Holy See).

The drafting, modification, and introduction of new precepts are reserved to the Holy See, though they may be proposed by the Prelature of Opus Dei.