This question seems to have been answered before, but, to the best of my knowledge, the current answer doesn’t seem to line up with the files that actually show up in a detached project.
The Expo docs state that the release channel should be changed in Constants.java, but this file doesn’t exist in my detached project (SDK 28). My experience here seems to line up with comments in this forum post, and this GitHub issue. We don’t have a Constants.java file in main/java/host/exp/exponent. Instead, there’s an AppConstants.java file in main/java/host/exp/exponent/generated. This file does have a RELEASE_CHANNEL variable, but it also has some “embedded responses” code that appears to be autogenerated. I’m guessing this file is affected by the contents of MainActivity.java and is altered by the build process, so I’m not sure I really should be changing it.
Long-story short, looking for clarification as to what we’re actually supposed to change in an Android project in order to change the release channel. I don’t think it’s Constants.java, because none of us seem to have that file. Thanks!