Navigating MO, it is possible to view two kinds of questions regarding errors within a book. The first kind are community-wiki questions which answers are a collaborative listing of found errors in a book (e.g.: Errata to Principles of Algebraic Geometry, Errata for Atiyah-Macdonald, Erratum for Cassels-Froehlich, etc.).
The second kind are questions that are more specific, concerning a doubt of the OP in a certain passage of the book (e.g.: A possible mistake in Walter Rudin, "Fourier analysis on groups"). The answers for this kind of question may or may not result in the discover of an error in the book.
Nevertheless, since both these two kinds of questions could be useful for a future compilation of an errata of a book or an entire errata database, it would be acceptable to create a new tag errata for these questions?