Enables a user or group to browse to a site page or library to access a specific content item when they do not have permissions to open or edit any other items in the site or library. This level is automatically assigned by SharePoint when you provide access to one specific item. You cannot assign Limited Access permissions directly to a user or group yourself. Instead, when you assign edit or open permissions to the single item, SharePoint automatically assigns Limited Access to other required locations, such as the site or library in which the single item is located.
As per my experience, It technically doesn't grant any permissions. Even if a user or group is specified limited, the user won't have access to anything. For example, user won't be able to access item or library (for which user is granted access) using the site home page or regular site navigation.
Since, limited access show up at site level. What resources does it make available for the user?
As the article describes, "Limited Access" permission doesn't actually give the user the ability to see those items but is instead used under the covers to make things work (rendering the user experience, etc.) Hope that helps!