At the moment, when looking at browser extensions via the Intune integration Client, you can see which browsers are in the environment and how many devices have them installed. After clicking onto it, you can also see the devices which have it installed. However, at the moment, there is no way to search for a device and see all the extensions installed. I would have to go through each extension separately and check if said device is there.
I believe it would be efficient to be able to sort by device, so that I could just click onto a device profile and see what extensions are installed, instead of having to go through 100+ extensions on the off chance one is installed.