Hi George. Looks like you're running an automated QA tool that is noticing undocumented tags. Well, good quetion. I made these tags up, but haven't yet documented them: partly because I wasn't sure whether it was a good idea to even use them, and wanted to see how I felt about it. Also given that they're specific to the island, I really wasn't sure how much documentation I should bother writing on the OSM Wiki, if any. I've only used them on this one way so far, I think. So "cobi" is for City of Bainbridge Island. I don't work for the city: it's just where I live. And "rdend" is short for "Road End", or to be complete, "Public Road End". That's the phrase the City uses to describe these protected areas on the island that were once or were planned to be roads down to the sea. They're often where ferries used to stop, before more roads inland were built, and a bridge to the mainland was built. Okay so the tags are really just copies of data that should be elsewhere. The city has a database, and I have a spreadsheet I'm using as I map each of the 60-or-so Road Ends. But of course I want just '''one''' tag at least, that can reference a list elsewhere. If there's a way of doing that using an existing tag, I'd rather be doing that, of course, than adding an unnecessary tag. Okay so "row" is a copy of the text in the "RIGHT OF WAY" field in the city's table of Road Ends. And "tidelands" is the text from the "TIDELANDS" row.

I thought it'd be good to have this data available to others. Ideally without unnecessary duplication. The city does have a ArcGIS account, and some of the data about Road Ends is in there. I could put each Road End into Wikidata, but my understanding is that there shouldn't really be anything in the official Wikidata dataset that isn't also on Wikipedia, which by implies it meets the notoriety criteria to end up in there. And I doubt that a collection of a few tens of yards of mud track on an island is sufficiently notorious to meet that criteria. Although having said that, an epic legal battle around access to one of them - Fletcher Bay Landing - ended up in the Washington State surpreme court, so there's that! There are several others that the city had to fight hard to make available to the public when the Road Ends were first organized about twenty years ago. That's a long answer. It's probably best I talk to my local OSM group about this rather than bother a some bloke in Germany who's just trying to keep OSM from falling apart. And I can do that, and point them to this discussion! Thanks for all the work you do on OSM.