TRMNL owners with the Developer edition add-on can click "Force Refresh" on any plugin settings screen to generate a new image, based on their latest settings.
But this takes a few seconds, and you can't reason about the graphic if your intention is to figure out a styling issue, or expose hidden information.
For this purpose we have Demo Mode.
What is Demo Mode?
To see how native plugins work in the browser visit usetrmnl.com/plugins/demo while logged into TRMNL.
Select a plugin from the list to view all 4x layouts with demo data. For example https://usetrmnl.com/plugins/google_analytics:
Using your own data
Simply append ?data=true to the plugin you're reviewing to merge in real data from your TRMNL account.
For example https://usetrmnl.com/plugins/simple_analytics?data=true injects actual traffic from our website. (You must connect the chosen plugin for this to work)
Choosing a specific instance of your plugin data
Suppose you've connected multiple calendars, and want to examine the markup of a specific one.
https://usetrmnl.com/plugins/apple_calendar?data=true&plugin_setting_id=xxx
Set xxx to the ID of the Apple Calendar you want to review. Find this in the URL of the plugin settings page for that instance of Apple Calendar.