I don't see any re-use tab, could you clarify? How should the source appear if it does not have that URL? If it's linked to the URL, it already shows up when you ctrl+f search in the wikitext editor.

The reuse tab in citoid
It failing to find that URL
It finding the URL that's actually in the citation

So, issue here is that they're attempting to search for a URL that Citoid would actually turn into that citation... but which isn't the URL that's used in the generated citation.

Actually, Citoid wouldn't turn either URL into that citation. 🤷🏻

In T381032#10380652, @DLynch wrote:

Actually, Citoid wouldn't turn either URL into that citation. 🤷🏻

Mmm. Warrnambool was my contrived example. I didn't realise that I was searching for a different url than in the wikicode. I am guessing that after citoid was used to insert the cite in 2001
(https://en.wikipedia.org/w/index.php?title=Warrnambool&oldid=1005705998) the website's url structure changed and they starting redirecting. I just asked on Wish linked above if the original user can provide an example from Google books for their jawiki use case.

If it is a case of websites updating their urls, I cannot see how citoid's search can be enhanced. This task may be invalid.

I am not 100% familiar with Phabricator, but I have marked the task as invalid. The task description is based on a false premise (formulated from my misunderstanding). The title Enhance search within Citoid's "Re-use" tab is very general and the description and dsicussion did not apply.