The permissions manager feature of Android is not complete yet and strictly speaking it should not be accessible. In 4.4.2 Google have removed the method that apps such as App Ops and App Ops 4.3 / 4.4 KitKat used.
As far as I know there is currently no way to access this any more. You will have to wait for Google to finish implementing it and provide a built-in method to access, or wait for someone to find another way to access it.
Quote from Color Tiger the developer of one of the apps on AndroidPolice:
Still not working, but here's a quick update:
See line 309 - those are
the allowed fragments that can be shown. AppOps was in that commit 3
days ago (line 329), but in the 4.2.2 build that's being sent out that
line is removed (we've decompiled the Settings.apk).
for a possible different entry point (another Activity to accept
commands to load the AppOpsSummary fragment), but it doesn't look
UPDATE: Apparently Google uses App Ops as an internal testing and debugging tool – it was never designed to be seen by end users, which is why it wasn't given a spot in the system settings, or even the developer options. Source