Build Forth interpreter into a C/C++ application

I happened to be reading an interview of Tom Zimmer
https://jimlawless.net/blog/posts/zimmer/ in which he states:
"When I work with other C programmers on large projects, I always build in a Forth interpreter into the application, for debugging purposes. The hardware guys love it, because it gives them so much power to figure out what is going on with the hardware. For software debugging, it is great because it gives you an interactive method of figuring out how to talk to the hardware before going off and writing a driver in C."
Would anyone have a "Hello, World!" type example of this technique?
I do see
https://gforth.org/manual/Integrating-Gforth.html
which ends with an ominous "More documentation needs to be put here." :-)