As what I saw into this post(Required Plugins Not Showing Up On Plugin List) NexEngine is intended to install with any plugin that uses it. But for NexAuth versions 1.3.5 and 1.3.6, it doesn't seem to be installing it while version 1.3.4 installs the engine. The NexEngine that comes with 1.3.4 isn't compatible with the newer versions.
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