This feature would extend the Usenet/Archive lens. It would enhance the user's ability to search for even more archived data if the feature can be included.
I'm not sure if Kagi can include this, but apparently, Wayback has a different index for "Collection Search" than their main index. There are things you can find through these searches that you won't be able to find in the main index.
Currently, kagi doesn't seem to include these as I can't find files via the Usenet/Archive lens that I would be able to using the "Collection Search." Please let me know if you want an example of a file found via the "Collection Search" vs the "Main search".
They also have different paths.
For example searching for a PDF via the collection search uses the path web.archive.org/pdf/search/<search term>.
I'm not exactly sure how it would be implemented, maybe via the Wayback Machine APIs?