Perhaps not surprising, but it seems vertical extent/placement is also affected by this. I was running a script (in Konsole 15.08.0) which prints names of files it's processing, and noticed some lines that happened to contain a Я (Cyrillic capital Ya) character in the filename were misplaced downwards by a couple of pixels when using the Oxygen Mono font (9pt).
Perhaps not surprising, but it seems vertical extent/placement is also affected by this. I was running a script (in Konsole 15.08.0) which prints names of files it's processing, and noticed some lines that happened to contain a Я (Cyrillic capital Ya) character in the filename were misplaced downwards by a couple of pixels when using the Oxygen Mono font (9pt).