This requires a re-interpretation of the S usage aspect: it then means usage of "sitelinks used in the sidebar", no longer "use of any sitelinks". This means that explicit usage (via Lua) of other sitelinks needs to be tracked as O (or X).

Given how widely this is used eg. on commons, this is a total show stopper. We will need to find another solution here, possibly a new usage aspect.

@hoo Access to "other" sitelinks is widely used? How/where exactly? Note that for the purpose of sitelinks, Wikipedias are considered to be in the same family as Commons.

In T178804#3703993, @daniel wrote:

@hoo Access to "other" sitelinks is widely used? How/where exactly? Note that for the purpose of sitelinks, Wikipedias are considered to be in the same family as Commons.

Commons very often links (in the page content) to other Wikipedias. This is the default behavior of https://commons.wikimedia.org/wiki/Template:Label which is used *a lot*(on 5M+ pages there).

Commons very often links (in the page content) to other Wikipedias.

Ah, but that's not a problem, Wikipedias are "in the family" for commons. And e.g. Wikibooks or Wikiquote linking to Wikipedia isn't a problem either, as long as it's the same language. These are the common cases, I believe. Basically, everything in the same row or column of the site matrix. Everything not in the same row or column would be O or X.

In T178804#3705857, @daniel wrote:

Commons very often links (in the page content) to other Wikipedias.

Ah, but that's not a problem, Wikipedias are "in the family" for commons. And e.g. Wikibooks or Wikiquote linking to Wikipedia isn't a problem either, as long as it's the same language. These are the common cases, I believe. Basically, everything in the same row or column of the site matrix. Everything not in the same row or column would be O or X.

Ah, I see… clarified the description now. This still seems awkwardly complex to me, though :/

@hoo I agree that it's not pretty - it's an optimization following the most common usage pattern. That tends to be messy. But it may allow us to ignore a good 90% of sitelinks changes, one of the more common kinds of edit...