What is the system text?
All words on the website that cannot be directly edited in the content, like for example the "cancel" button in a popup or the "filter" header when searching products. Also for the backoffice all text in all modules, like the field names etc.
How to change them?
In the CMS we go to the module settings and go to tab "translation". From there we can add or update the list of words or sentences. The ID is the key text, this cannot change, and all columns after are the translation in every language as configured in the application.
This translation tab is currently only available in the CMS, but will be added to other modules as well in a next version.