This is a tracking category for CS1 citations that have |edition= errors.
|edition= has extra text
The templates are responsible for static text rendered in the citation. When |edition= is used in a template, cs1|2 adds the abbreviation 'ed.' to the value in the parameter so:
|edition=1strenders as:
The templates emit this error message when various forms of ed, edn, or edition are found in the value assigned to |edition=.
To resolve this error, remove the extraneous text from the parameter value.
Pages with this error are automatically placed in Category:CS1 errors: extra text: edition.