It is hostile to power users, but gracious to unsuspecting users who might have a sneaky person install extensions on their browser to steal their data/spy on them. In any case, a real power user could always use a developer build and set that flag.
...this one?
>>Even installing the "Developer Edition" didn't enable to me to install self-built extensions (yes, with that secret flag).
I would guess that they are trying to install is actually broken.