[NiLuJe]

@barsanuphe: Yup, nesting was broken in FW 5.4.2, and it hasn't resurfaced since.

I was thinking of using this with the Calibre Kindle Collections plugin, most likely by making it understand the json schema used by the plugin, since the plugin already takes care of a number of sanity checks (namely the uuid/ASIN handling of each book).

FWIW, the schema is as follows:

{
	"<CollectionName>@<Language>":
	{
		"items":
		[
			"<hash>"
		],
		"lastAccess": <epoch>
	}
}

So, as an example with a few different types of hash, that would look something like:

{
	"Apps@en-US":
	{
		"items":
		[
			"#B006VZUZV2^AZW2"
		],
		"lastAccess": 1344387337000
	},
	"Brandon Sanderson@en-US":
	{
		"items":
		[
			 "*c98b6567481d950dccad195379053e2539f1d75c",
			 "#12e45a36-0410-4caf-b32d-dc807713d8e9^EBOK"
		],
		"lastAccess": 1234567889976
	}
}

(The indentation is all mine, for formatting purposes only).