Patron Plugin Pro Documentation
Customize Notifications for Summaries for Patron-only posts in Post listings
If you set the summaries/excerpts in post listings to be protected for locked posts as described here, in this section you can customize the notifications which will appear for these posts in post listings.
You can change the text of the notification, the font size and various other visual properties.
You can even use your own custom banner if you wish, which can be an image.