Actually, I did some searching and it seems that most RCTs don't actually list the contents of the placebo pill. I found this article which describes the problem:
Thank you. Very enlightening and happily agrees with both your statements (that they usually aren't sugar pills) and mine (that placebos themselves may have medical impact).
https://www.reuters.com/article/us-whats-placebo-idUSTRE69H5...