Here's the JSON for Graven: https://pastebin.com/bup18Te
Unfortunately, I haven't been able to fix all issues I've found just yet, so I've had to fix the output by hand. The export from the converter works just fine now, but Foundry doesn't accept the JSON. There's something strange going on with the way the new dnd5e system in Foundry processes tool items like "Smith's Tools" for example. It expects some peculiar values that aren't used in other places...
At any rate, I'll get to the bottom of it and I'll let you know when I found a permanent solution.