{{Wj}} inserts the code ⁠ literally, which produces a U+2060 WORD JOINER in the rendered wiki-page.
Usage edit
This is a convenience template for the zero-width no-breaking character, U+2060 (⁠).
It is completely invisible in display, but has the effect of acting as a multi-line no-breaking point for text inside a word that otherwise would break. No-break space and No-break hyphen dashes (‑) are already multi-line unbreakpoints, but this template allows the special insertion of invisible unbreakpoints inside words.