It does seem like it is NavTech. I signed up for their dev access but they have a ton of different formats for their data and I didn't immediately see something that matches. They mention on their forum that the car makers customize the formats for storage. It looks like it is POI data. There are also code types for the type of point. So I may be able to decode more from those docs. But for now, much faster progress was made by just looking at the data.
For those interested. After the 256 byte block (which I need more saves to decode), an entry looks like this:
First two columns are lat/lon pair. Column 7 is obviously a hex string and it turned out to be the obvious thing. It is ASCII for the location name. In this case "MAIN ST.". The "44" may be code for a charge site. On my data, it is 44 for charge stations and 0 for home location. But I need more data. 3000 matches the code format for NAVTECH POI but couldn't find what that code meant. All my points are 3000. 4294967295 is consistent for my points also so could be a UID for me. The three numbers in the middle vary (all others match):
Here is the variation on the three middle numbers.
-1719561536 1027 479
-1719627072 672 982
-1722576175 976 1217
-1722576189 1109 604
-1721527600 202 340
A few more datapoints to decode the initial block and I will start writing my own files.