[taos]

It's possible that the libnickel patch `Allow searches on Extra dictionaries` doesn't work for the latest firmware 4.8.10956.
You can still replace the space after "Extra:" with the patch but the "Extra:_" in front of the dictionary name is not shown anymore when you look up a word from an epub. Instead of e.g. "Extra:_da - English" now "Dansk - English" is shown in the drop-down menu (depends on what you used as name in the database). However, as soon as you choose it, the name changes to "English - English" and the well-known error message is shown: "You don't have an English dictionary installed." (the same as on an unpatched system).
In addition, the additional dictionary languages are now also shown if there's no corresponding "ExtraLocales" entry in Kobo.conf.

Update: It seems to work if the name of the dictionary in the database is changed from "Dansk - English" to "Extra:_da - English". Thanks to jackie_w for this workaround!