variant edition; special chapter
Used in manga and magazine publishing for a special edition or a chapter that appears outside the regular series, often in a different magazine or as a standalone release.
A special chapter of the popular manga was published in another magazine.
This variant edition is drawn with a slightly different setting from the main series.
Compound of 出張 (business trip, going out) and 版 (edition), referring to an edition that 'goes out' to a different publication or venue.