Gramps:Side bar translation
Manual on how to translate the sidebar, and how it works.
Only a system translator can edit the sidebar labes, so you should contact eg bmcage and give him the translated strings.
How to edit side bar
Read Mediawiki manual
What to translate for Gramps
The Gramps sidebar is: MediaWiki:Sidebar.
The target links are fixed to the english pages and cannot be changed. The first column is the target. Click on it for those defined by Gramps. The last columns contain the labels that should be translated: