How to change grey info message text?

If you’ve found an incorrect translation within the Sensei plugin, you can feel free to submit a change to GlotPress:

https://translate.wordpress.com/projects/sensei/

And we have a Getting Started Guide for more information about this process.

But if you’re looking to translate specific text on your site, we also have a great support guide with information about that:

https://senseilms.com/documentation/translating-sensei-lms/

As a bit of an aside, if you’re looking to offer your courses in multiple languages we have specific guides with information about doing so using Polylang and WPML.