Comment by fweimer

Mozilla has disabled privacy controls in the past without informing users. For example, they removed the “prompt when setting a cookie” (so that you could reject/accept/accept for this session only) without a replacement. Newer versions just accepted all cookies as persistent, non-session cookies automatically. There are other examples like this.

It's difficult to deal with because as the code evolves, so do the configuration settings. The rate of change is high, and it's not always obvious what is relevant to users (and whether a new feature increases or decreases privacy!), so it's hard to communicate this in release notes.