Fenix: [Bug] USB Keyboard -- Unable to unhide (or even access) Navigation Bar

[gamepad-coder]

Steps to reproduce

1. Plug in a USB Keyboard to an Android device running the latest version of Firefox Nightly.

2. Navigate to any site (i.e. be on a webpage tab, not on the home screen or other setting screens)

3. Scroll down the page using your finger or stylus on the touchscreen.

4. The Navigation Bar / (aka) URL Bar / (aka) Address Bar at the bottom should now be hidden from view, and the page will fill the screen, no Firefox interface currently visible.

5. The problem. The USB keyboard cannot unhide the Navigation Bar. No USB keyboard press nor hotkey is able to navigate to the Navigation Bar. It remains hidden and impossible to interact with via the USB keyboard.

Expected behavior

F6 is typical Firefox input to focus the Navigation Bar on Desktop, and is expected to work with a keyboard here.

Ctrl+L is common in many Android browsers, including the current stable Chrome for Android.

In the current release of vanilla Firefox for Android, the Navigation Bar can be reached / unhidden with a USB keyboard by scrolling to the very bottom of a page. Holding down PageDown to repeat the function until the bottom of the page is reached is currently the only viable way to unhide the Navigation Bar with the keyboard alone (in the stable release branch on Android).

But in the latest Firefox Nightly, it is impossible with a USB keyboard alone.

Actual behavior

An additional device or input interface is required to browse when a USB keyboard is attached.

Further Information & Use Case

I am using an IBM Spacesaver II. It is plugged in via USB and mouse functionality is included in the keyboard.

My Android device is out of arm's reach.
Mouse works as expected across the Android environment.

However, if Firefox Nightly has the URL Bar / (aka) Navigation Bar / (aka) Address Bar hidden, it cannot be reached even using the mouse / (aka trackpoint) on the keyboard.

Summary

Use of Firefox Nightly is impossible using a USB Keyboard alone.

Device information

App Name : Firefox Nightly
Version : 81.0a1
Build ID : 20200813092915

Unrelated

I absolutely love this new Firefox.

[headbank]

If I may, I have a couple of points to broaden this bug's scope:

1. It applies probably to any external physical keyboard. I can confirm same issue with a Jelly Comb foldable Bluetooth keyboard.

2. My Bluetooth keyboard also has a touchpad that supports scrolling, but using this touchpad scroll in Firefox does not unhide the toolbar either. Nothing to test with but I'd bet that scrolling with a physical mouse (Bluetooth or plug-in) would not work either.

3. Worth specifying that hide as well as unhide is equally unsupported with these input methods. So, if the toolbar is displayed, while you are using keyboard/mouse you are stuck with it onscreen.