OK, that makes sense. I was going to suggest adding the extra parameters to the beginning rather than the end of URL, so the search query is still at the end, but it looks like I can just add ns0=1 to my initial search query to avoid the redirect, which works well enough. Thanks for clarifying!

A recent update seems to have added another inconvenient redirect: https://en.wikipedia.org/wiki/Special:Search?search=zybjykht now redirects to https://en.wikipedia.org/wiki/Special:Search?search=zybjykht&ns0=1. Is this intentional?

In particular it looks like this is implemented by src/mediawiki.action/mediawiki.action.view.redirect.js redirecting to the "canonical" URL.