The most quoted piacular formula is agricultural. A farmer needs to thin a sacred grove on his own land, which means cutting trees that belong to a god. Cato tells him to offer a pig and to say a prayer that begs pardon of the deity to whom the grove is sacred, addressing that deity as whichever god or goddess it may be, and asking leave both for himself and for the man who does the cutting. He is then to repeat the offering each day the work continues.
The formula is remarkable for what it concedes. The offerer does not know who owns the grove, does not know whether the owner is male or female, and says so in the prayer rather than guessing. Roman religious language is full of such hedges: alternatives named so that the right one is certainly included, formulae covering a deity by name or by any other name preferred, phrases reserving the possibility that the offerer has got it wrong. This is not vagueness. It is the same exactness that made a misspoken word invalidate a rite, applied to the case where the required information is unavailable, and the solution is to make the uncertainty explicit inside the formula so that the form remains correct.
The prayer also declines to explain itself. It does not say why a grove belongs to a god, what the god will do if unpropitiated, or what the pig accomplishes. Roman religious texts of this kind are procedural throughout, and the theology has to be inferred from the procedure, which is a large part of why the interpretation of Roman religion has been argued over as much as it has.