It is always a bit of a struggle to find the right place to translate
ubuntu-docs. I have several links in my web browser's favorites, but it
is always a wild guess which one to use, see below. From an earlier
email discussion I understand that /trunk/ is the best choice. This
seems to be the latest development version.
In this case, I guess /bionic/ and /trunk/ refer to the same
translation, although I see a slight difference under ‘Last changed’.
Bionic and trunk are both fine - they are synced. Vivid is EOL since long.
Please note that Ubuntu Desktop Guide consists to > 90% of GNOME Help
nowadays, so the number of translatable strings in the ubuntu-docs
package has been significantly reduced. I tried to explain that here: