Q: Is the collective name "Xbox Series X/S" or "Xbox Series X|S"? Which format is used on Wikipedia?
A: Microsoft brands the family as "Xbox Series X|S". This style has been adopted by many sources, while others use "Xbox Series X/S". The former formation can cause problems with Wikipedia's text markup when used in links: [[Xbox Series X|S]] will generate the text "S" with a wikilink to "Xbox Series X".
For this reason, the piped character is a forbidden character in page titles.
While it is possible to work around this using piped links ([[Xbox Series X and Series S|Xbox Series X|S]] produces Xbox Series X|S), more editors will simply copy and paste the visible wikitext and end up breaking existing wikitext, particularly in tables and infoboxes. It was thus decided to prefer the "Xbox Series X/S" approach, which has no issues with any wikitext formats.
