It’s totally separate, it’s not a mod. It’s more of a QoL trainer (D3 TurboHud comes to mind) and very configurable.
You just copy it into Grim Dawn directory and run it.
You can always play a normal version of Grim Dawn at any time as it doesn’t modify the game’s files.
Everyone is different in what its features they are using [Tool] Grim Internals
(not sure if notification feature is in the OP or rather in one of the lasts posts because it is an early release)
Monster Health bars it has might have been the reason we have them natively in Grim Dawn now.
My best memory from Grim Internals:
