Here's something new. AMA conducts elaborate meetings of its RUC (relative valuation) committee, passes those recommendations to CMS, which heavily influence the assignment of CMS values and pricing to CPT codes.
Very lengthy minutes are left behind online. The RUC Minutes home page is here:
This either requires no registration or an email registration. For example, the May 2019 RUC minutes are 376 pages of detail:
Separately, through the AMA Store, AMA sells online annual subscriptions for $320 to the RUC RBRVS Database, which gets you into definitions, RUC decisions, valuation, and utilization of every CPT code. Search AMA Store for "RBRVS Data manager Online." (One version here.)
After CPT meetings, with a delay of a few weeks, AMA publishes a brief table whether each code agenda item was approved, disapproved, or tabled. AMA calls this "Summary of [CPT] Panel Actions." See here. May 2019 is here.
Finally, if of interest, an AMA CPT confidentiality statement sample is here. It's aimed primarily as protecting AMA CPT copyright interests.