When I was working as a carpenter and later as a contractor here in the Northwest, that is a common styling for deck fittings.
If we pre-made them in the shop, we used a router table. Common sytles were either with a 45* or 30* champhor , endng up with 45* or 60* in relation to the top. If 6" posts, then we started out with 8" square stock 2-3" thick, so that was a good overhang around the posts. If On the posts, we usually dressed those up with V-Grooves.
If we did them on-site, then we did it on a table saw.
You could dress it up with copper caps. But even though we only have 52 days average that is doesn't rain here, if you do it that way and seal it, the cedar around here ages well and is fairly weather worthy. We still seal it though.
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