This is meant to be a PowerShell alternative to https://gist.github.com/derjanb/9f6c10168e63c3dc3cf0 for Windows users unable to compile the leveldb Python module.

extract_tampermonkey_scripts.ps1

# Copy your Tampermonkey storage.js into the same directory as this script.
# It'll extract the user scripts from storage.js and write them as .user.js files
# in the current working directory.

add-type -as System.Web.Extensions
$JSON = new-object Web.Script.Serialization.JavaScriptSerializer
$obj = $JSON.DeserializeObject((gc storage.js))

foreach ($key in $obj.keys) {
	foreach ($val in $obj[$key].value) {
		if ($val -match "\r?\n//\s+@name\s+(.+)\r?\n") {
			$val | out-file ("{0}.user.js" -f $matches[1])
		}
	}
}

My storage.js file begins like the following:
(function() { Registry.require(["promise"], function() { var f = rea.FEATURES,

JSONLint validator also tells me that the very first character is faulty. The open bracket.
@calraith How does your storage.js begin?

TY so much!
I wish there was an upvote in github to let more users know about this!

@calraith Where is this so-called Tampermonkey storage.js file located? The one I found at %appdata%\Opera Software\Opera Stable\Extensions\dhdgffkkebhmkfjojejmpbldmpobfkfo\4.7.54_0\storage.js is just 13 KB of JavaScript, not JSON. So I get the same error as @BangDroid and @Remonell.

@calraith Where is this so-called Tampermonkey storage.js file located? The one I found at %appdata%\Opera Software\Opera Stable\Extensions\dhdgffkkebhmkfjojejmpbldmpobfkfo\4.7.54_0\storage.js is just 13 KB of JavaScript, not JSON. So I get the same error as @BangDroid and @Remonell.

I guess this script did nothing. The actual scripts should be in User Data\Default\Local Extension Settings and stored in db not some random storage.js.