If you're managing multiple environments for any export platform(s), like MailChimp or Klaviyo, etc; you may find it useful to save these different environments (for example, platform API keys and settings) as custom presets that you can Switch between as needed.
To do this, select the platform you would like to upload your HTML email to in the plugin's "Export" panel, enter your API key(s) and specify any other settings or toggles, then click on the Presets List icon button, enter a label (for example, My MailChimp Client 1) and then click the Create Saved Preset button to save your custom settings preset.
You can find this new option in the platforms drop down selector under the Saved Presets group, where selecting any of your saved presets will automatically populate the plugin export input fields with your saved settings.
You can Update or Delete any saved presets by clicking the Pencil icon button when you have the preset option selected (as per the video screencap above).
Saved export presets are mirrored to Figma’s local storage for the current user, so as long as you’re logged into Figma on the same computer, you can reuse them across multiple Figma files.