Okay, now I see the error of my ways. I had been trying to search open tabs from an open tab of my default search engine: duckduckgo. Searching for an open tab FROM A NEW TAB (as in your screenprint) does work - awesome.
Its usefulness is somewhat restrictive in that - for example - if I had an open tab where I had searched for ‘baseball’ at youtube.com and I searched open tabs for ‘baseball’, it would have identified the youtube open tab, but if I had searched for an open tab with the search term ‘youtube’, that open tab would not be found (although other open youtube tabs would have been found with other youtube subjects shown - seems strange - inconsistent - to me).
If I search for the term “router” and I’m looking for an open tab “tomsguide.com/us/home-router-security,news-19245.html”, it did find that one using the current way of searching.
Here’s another anomaly: searching for an open tab using search term ‘pocket’ does not find the open tab for “getpocket.com/login?e=2”. Seems like it should be able to find the open tab just from the search term “pocket”. Lots of other sites have their internet address with the leading word “my” in front of the rest of the address, and those would not be found either.
The way of searching open tabs as it exists today is definitely better than nothing.
Many thanks for your help with this. Maybe at some point in the future, the tab search feature can be expanded to look for any open tab with any of the search terms, rather than just the exact, complete root internet address.