This is an extension, rather than an external tool, so just double-click the downloaded Dashboard.jaext file, and it will install itself in your config directory (won't be wiped out when you update jAlbum itself).
It shows up as an entry on the Tools menu (even easier, just hit ALT-D). If you have an open album project, invoking this extension brings up a little popup window where you can examine things like the skin variables, engine settings, and so on, and they're all sorted alphabetically.
This is probably most useful for skin developers - when you're getting a template error, and you can't remember whether you called it breadcrumbFontSize, or breadCrumbFontSize, or bcFontsize, this can help you sort things out very quickly.
ETA: TomCee has vanished (isn't responding to emails, either, so I don't know why he hasn't been here in a couple of years), and his storage account has expired.
Happily, before my PC died a horrible death, I had, in fact, backed up this sucker. Attached. (I've also stashed copies of the source files, if anyone is after them.)