I believe I have found a rare instance of the groups.io user interface being inaccessible to the blind or visually impaired.
Description: Items on Files->New/Upload menu cannot be activated without mouse.
To reproduce: Click on Files in the left navigation menu. Click the New/Upload button. Use cursor keys to place focus on a menu item. Pressing enter or space bar to activate the item will not work.
Desired behaviour: When a menu item is highlighted (has focus), the item should be activated by pressing enter or space bar.