Which are the mandatory markers for a minimal USFM file?

[kavitharaju]

As per the these tests, it expects \id, \c, \p and also \v. But text inside a paragraph is not mandatory

• https://github.com/usfm-bible/tcdocs/blob/471a15103622813ddd4e4eb13b17bb464bf02cbf/tests/mandatory
• https://github.com/usfm-bible/tcdocs/blob/471a15103622813ddd4e4eb13b17bb464bf02cbf/tests/paratextTests/NoErrorsEmptyBook/origin.usfm

But the following tests seem to contradict the above set rule

• Only id https://github.com/usfm-bible/tcdocs/blob/471a15103622813ddd4e4eb13b17bb464bf02cbf/tests/paratextTests/NoErrorsShort/origin.usfm
• Empty c https://github.com/usfm-bible/tcdocs/blob/471a15103622813ddd4e4eb13b17bb464bf02cbf/tests/special-cases/empty-c/origin.usfm
• Only id https://github.com/usfm-bible/tcdocs/blob/471a15103622813ddd4e4eb13b17bb464bf02cbf/tests/special-cases/empty-book/origin.usfm

[KentSpiel]

We have a use case for creating a Paratext project with only Book introductions. We want to publish the book introductions on the DBL in order to establish copyright. In other words a project with no chapters. Would such a project be valid USFM?