As for the missing translation of the Export button, officially we support only English language. Translations to other languages are community-driven. For more information see the Contribution documentation section.
The message is under /* Scheduler messages */ in the linked German message file and looks like this:
"pdf": "Exportieren als PDF",
To have the message translated in French, you can add the entry:
"pdf": "...French translation here...",
in your kendo.messages.fr-FR.js file locally, or contribute in the repo as explained in the Contribution article linked above. In this case, the message will be included in the messages files that we distribute.
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