Comment 14 for bug 43464

If Quod Libet says "Error grabbing key 172, 0x853bc00" it means that something else is intercepting the key. Close all applications potentially using the multimedia keys, start Quod Libet at a terminal (*after* closing everything), then try. If you still see that message at a terminal, it means something - probably some GNOME core component - is still grabbing the key. If that's the case, this a "bug" in GNOME - I'm sure whoever made the actual change will claim it was a feature.

The Debian people did not see D-Bus as causing the breaking, towolf did. Thet Debian bug report was simply about Quod Libet using a deprecated D-Bus API and had nothing to do with multimedia keys.