@Bryan and @gmerritt123. Thanks for the responses. I updated my initial comment with my Bokeh version (v2.4.3), that I get the same behavior/question in Bokeh v. 3.0.3, and a minimal reproducible code example.
In the thread that @gmerritt123 referenced above in which @Bryan is responding to a question by @gmerritt123, it seems like the solution is to use the jinja2.Template class with the bokeh.themes.Theme method.
Can you give an example in the simple code I posted above that would make my title text be in the Google Font “Open Sans”?