I've been looking for something like this for a while. I used a similar plugin like this some time ago, but wasn't completely happy it. This one is as simple and straight forward as it gets. Kudos.
EDIT 22-02-2022: Bringing this back to 2 stars for now as it is not so excellent as I thought. It crashes with PHP8. And PHP 7.4 is end of life at the end of this year. There is no follow up on the support section either so I guess I should look for a different solution. Too bad. Expected a little more from Automattic to be honest.
Does what it says it will do. You create your glossary entries and it does the rest. I like that it defines a custom post type so that you can create a full page of glossary entries by filtering on the type.
Only thing keeping it from being 5-stars is the absolute lack of customization options, but it's open source, and free, so that's definitely not a functional flaw.
Nice plugin, folks. Thanks!