How to upgrade standalone plugin?

I'm running TiddlyMap standalone in Firefox on Windows and it seems I can only install the plugins by dragging and dropping the links from https://tiddlymap.org/#Installation . But the core plugin on that page is out of date: it installs v0.17.7+9982 whereas Github is at 17.20. I cannot for the life of me figure out how to update the plugin in the standalone to 17.20. Help! I've tried using the browser tools console and I do not understand how this plugin gets installed.