This is a browser preview made to look like the in-game banner. Colours, speeds and layouts match closely; the final look in Roblox is the reference.
Paste an effect from your EventBanner Effects file and it plays at once. You can paste one effect, several, or the whole file.
You can also drop a .lua file onto the box. Errors point to the line that needs fixing.
Bold rows are the ones you changed. ↺ puts a value back to the plugin default. Hover a name for what it does.
Your work is saved in this browser automatically.