that hyperlink also doesn't work apparently but you can paste this into the url bar opera://settings/keyboardShortcuts

@bloor88 if you're used to different keyboard shortcuts than the defaults, you can change them in settings > shortcuts (at the very bottom under advanced) > configure shortcuts (or click this link)
as for why the forward mouse button doesn't work, i have no idea and am also annoyed by it

@daymi4n: didn't know chrome extensions work on opera. thanks!

It'd be nice to have a way to save settings or adjust how long the pauses between sentences are, but this is still the best tts extension on opera i've seen yet