Newer Dell Notebooks equipped with USB-C or Thunderbolt controllers allow the configuration of those technologies in the BIOS under a single entry. However, the layout or display of this was somehow confusing as features that were "not installed" were still visible but grayed out (per the image below).
(Figure 1: Old System BIOS)
Following the release of newer BIOS versions, like the example below from Precision 5520 with the latest BIOS 1.1.3, this changes into separate BIOS entries.
USB Configuration:
(Figure 2: Under the System Configuration section, you can find settings for USB Configuration)
Dell Type-C Dock Configuration:
(Figure 3: Under the System Configuration section, you can find settings for Dell Type-C Dock Configuration)
Thunderbolt Adapter Configuration:
(Figure 4: Under the System Configuration section, you can find settings for Thunderbolt Adapter Configuration)
The aim is to improve the display of the installed technology and limits any confusion. Dell offers BIOS versions for systems with this technology, and we recommend maintaining your system with up-to-date BIOS versions as good practice. The latest versions can be found on the Dell Support site under the Drivers & Downloads section for your system.