Two relatively unknown Chrome OS devices mentioned in the Chromium Gerrit database under codenames 'sarien' and 'arcada' will feature unique keyboards with a top row explicitly designed to handle function keys, according to a recently sighted code commit. The commit applies most directly to the testing of the new layout on sarien but notes that both that device and arcada use a keyboard layout and "action/Fn-key handling" that's different from traditional Chromebooks, with the duo in question being most likely made by Dell.
The purpose of the test is to ensure that the newly created layout is recognized by Chrome. Nothing in the newly discovered commit guarantees the extra row is phyiscal, leaving the possibility of something akin to the Touch Bar of Apple's newer MacBooks making its way to the Chrome OS ecosystem.
What we know so far
Previous appearances of arcada and sarien in the repository have suggested that the codename points to a series of devices to be released by Dell. Sarien may also arrive in at least one variation that allows the display to completely detach from its keyboard, similar to HP's Chromebook x2, in addition to a more commonly used 2-in-1 format.
That was indicated by a prior commit in the Chromium Gerrit which pointed to a "tablet_detachable_bypasser" used to wake up or put the device in sleep mode.
Other information about the device has been equally speculative, with some code pointing to the use of Intel's 8th-Gen Whiskey Lake series processors while code buried deeper has hinted it could ship with Intel's unreleased 10nm Cannon Lake architecture. As pointed out by the source, there have also been no fewer than two USB Type-C docks spotted in the repository as well as commits pointing to compatibility with a Wacom stylus.
Why the new keyboard?
The ability to dual-boot the unannounced devices into either Windows or Chrome OS is among the more prominent guesses regarding why the keyboard would need to be so different as to include support for function keys. Keyboards used with the former platform typically ship with the top row of keys populated by the hardware keys as a way to interact with any given application or software depending on how those respond to presses of the keys. They're typically labeled "F1" through "F12."
On Chromebooks, those are generally replaced by keys that interact at the system level or directly with actions in the browser. For instance, the F1 key is replaced by a "back" arrow icon and related functionality while a 'refresh' button is placed instead of the F3 key.
The layout typically used on a keyboard also applies to other operating systems such as Linux and macOS. Google has continuously worked to ensure that Linux software that's accessible on most new Chromebooks runs more natively on the platform. So another speculative answer regarding the reason for the newly added keyboard layout could simply be that Dell wants its Chromebook's to be easier to use with the Linux side of things.
Last, but not least, yet another possible solution to the riddle may be found in the recent addition of multimedia key support that's been added to the Chromium Gerrit. That's not set to arrive in an official capacity until Chrome 73 in March and points toward better support for media playback control on Windows -- which already utilizes hardware-based multimedia keys. However, the addition of a new keyboard layout for sarien and arcada could feasibly be meant to help users access the same features in Chrome OS, pending the addition of further code behind the new keyboard.