Found a direct UI hit at least with some resource strings in the last/mainline branch that checks out from the repo by default which is cm-14.1. It started by finding a repository that happened to have the words settings and application in its name was a very strong clue to start with. In the screenshot above you can see that the UI reads Root access and that is what we find verbatim in this resource file.
<!-- Setting checkbox title for root access -->
<string name="root_access">Root access</string>
<string name="root_access_warning_title">Allow root access?</string>
<string name="root_access_warning_message">Allowing apps to request root access is very dangerous and could compromise the security of your system!</string>
<string name="root_access_none">Disabled</string>
<string name="root_access_apps">Apps only</string>
<string name="root_access_adb">ADB only</string>
<string name="root_access_all">Apps and ADB</string>
Running a blame on that block of text lead to this diff
Going back to the branch that is installed on the device, or at least the closest stable matching variant, I do in fact find that root access resource string being present. I'm hoping there's something interfering that I can twiddle to bring that option to the forefront again because it's not showing up.
Doing a blame on that version leads to this commit...
- Root over ADB is now disabled by default on non-eng builds
- Requires support in su binary and adbd
- Root access can be configured to use ADB only, apps only, or all https://github.com/CyanogenMod/android_packages_apps_Settings/commit/c39be56248000ac1c88909874b28a80f5370fb2a
Snooping around further in that diff, it looks like I may be out of luck, or apparently at the time it was decided that user builds do not get this feature, but engineering builds do.
private boolean removeRootOptionsIfRequired() {
// user builds don't get root, and eng always gets root
There is some variation in that branches evolution where this behavior was modified. One last study to see where things wound up is in order.