Hi,
There’s currently no i18n support in Orthanc. So you’ll have to modify the Orthanc Explorer files directly.
FYI, here’s a docker sample that shows you how to serve a customized version of the Orthanc Explorer through the ServeFolders plugin:https://bitbucket.org/osimis/orthanc-setup-samples/src/master/docker/serve-folders/. With such a setup, you don’t have to recompile Orthanc to embed your modified Orthanc Explorer.
Best regards,