WordPress.org

What text does this plugin modify (aka filter)?

This plugin potentially modifies the post content, excerpt, title, and comment text.

Why do my sentences still appear to be separated by only one space despite the plugin being active?

Did you use two spaces to separate the sentences when you wrote the post? This plugin only retains the appearance of those two spaces when the post is viewed in a browser; it does not insert a second space if there wasn't one originally present.