This also appeared while clearing the forsythia:
It’s the guy line anchor for the fallen utility pole, abandoned in place when the crew installed the new pole.
The rod turned freely in its underground anchor, but the nut is apparently frozen to the rod. I deployed the bolt cutter on the cable and hauled the carcass into the Basement Shop:
Steeping the nuts with Kroil for a few hours relaxed them enough to submit to gentle suasion, whereupon the cable sproinged as the last nut released the clamping force:
As far as I can tell, the clamp hardware dates back to the pole’s original installation in 1940 and is in fine, if not pristine, shape.
The bolt shanks have an oval section matching the holes in the plate, so the bolts don’t turn and the crew needs only one wrench. They don’t make ’em like they used to!
I have no idea what I’ll do with these things, but they’re entirely too nice for the steel recycling bucket.
The Smell of Molten Projects in the Morning 
I tend to save these kinds of things as well. While speaking with my parents the other day discussing some of the things going on in the world and some of things I have saved, I was told that “you would think you had grown up and lived through the depression”. There’s no doubt I’m very much like my grandfather and a pack rat, or in the words of Adam Savage, “a high functioning hoarder”. There is merit in saving things and being able to retrieve them when needed, well that, and some things are just plain cool and worth saving and admiring. Sometimes for their functional and intended use, other times for their rustic patina as “shop art”.
At some point, I know I’ll build a thing resembling a button-head steel bolt …
I had absolutely no idea oval-shank bolts were a thing. Never heard of such nonsense! Seems handy.
Definitely prettier than a square-shank carriage bolt and much harder to conjure in the home shop. I expect a patent deep in the procurement process … [grin]