The "Show"/"Hide" links in various special pages options box should be localizable per item.
Identified special pages:
Note that Special:NewFiles uses this approach.
Currently, every one of them is produced using the same message ('hide' or 'show'), which makes it impossible to translate them correctly in languages which would require them to be conjugated or something.
Apparently this is a problem on ce.wikipedia, it was reported to me by one of the users there.
See also: T20577: replace "show/hide" by an icon