When you hide layers in an imported file or a linked file, the layers are still available to the Revit project, but they do not display in views.
You can specify how to hide layers in each view. For example, you can display all layers in one view, but hide some layers in another view. You can redisplay the layers later, if needed. If you are not sure on which layer an object resides, you can query objects in layers.
Revit lists the layers in the file.
The layers are hidden in the current view only. To redisplay hidden layers, repeat this process and select the desired layers.