SiteSearch от Janghou

SiteSearch the site in your tab easily with quick adaptable depth by simply clicking the path segment.

Search with different configurable search engines, or all at once!

Also offers to search for a filetype, in a region or a specific language, if your search-engine of choice supports it!

Not working in the latest Android version due to bug #1625593
https://bugzilla.mozilla.org/show_bug.cgi?id=1625593#c6 (fixed in Nightly 5-2-2020)