# Visit [[ https://www.mediawiki.org/wiki/Special:Preferences#mw-prefsection-rendering | Special:Preferences > Appearance ]]
# Under "Advanced options" there's a preference labeled
"Threshold for [[ https://www.mediawiki.org/wiki/Special:Preferences# | stub link ]] formatting (bytes):"
# Click the reddish "stub link" link.
Result: you go back to the main Preferences page.
Expected result: I expected a link to a missing page (because reddish) that's intended to more information about "stub links".
But this behavior is actually intended, see [[ https://phabricator.wikimedia.org/T11886#142487 | brion's comment]] in {T11886}. The 'stub-threshold' message is the HTML:
Threshold for <a href="#" class="stub">stub link</a> formatting (bytes):
If you look carefully at Preferences, you're not seeing a redlink to a missing explanation of what a "stub link" is, you're seeing the actual presentation of a stub link via a link styled with class="stub".
The fix is for the message to be clearer, e.g.:
"Threshold in bytes for stub link rendering (sample):"
While I'm here, the qqq.json doc for 'stub-threshold' gives the wrong tab and is unhelpful (ditto 'imagemaxsize'):
Used in [[Special:Preferences]], tab "Misc".
Note the entire feature is controversial, {T30426}.