It's funny how the definition of composting toilet has changed since RVers started using them :).
A composting toilet used to be something that did the composting itself. Meaning it would hold several years worth of poop.
But just last week someone told me she had a composting toilet in her van, and it turned out that what she meant was that she had a bucket and a plastic bag :-).
The top comment on that video has a good link about disposing of the non-composted stuff that you get in a plastic bag, from a so-called composting toilet:
https://www.livesmallridefree.com/blog/where-to-responsibly-empty-your-composting-toilet