When inserting text in text input (e.g. Dupes' names or base name), pressing modifier keys (Shift, Alt, AltGr, Ctrl, Caps Lock) will insert unicode characters (between U012E and U0141 it seems – I can try to list them if needed). The modifier key will still work as modifier key. E.g. If I want to name a dupe "Kay" (pressing shift to get upper-case K), when pressing the shift key, it will insert "ĭ" (not sure what was the exact character), then insert "K". Arrow keys, back space, page up/down and enter at least work as expected.
This is on Ubuntu 18.04. The problem is the same regardless whether I use a translation mod or not.
Run QoL version of ONI, start a new game, try to rename the base and press one of the modifier keys (left shift, left ctrl, left alt, right shift, right ctrl, right altgr, caps lock). A character will be inserted.