Resource Optimizer Extended Compatibility
The standard Resource Optimizer feature is offered as a setting with Adaptive Acceleration. You can enable it to compress and cache resources, such as JavaScript, CSS, and font files. Resource Optimizer Extended Compatibility enhances this standard version to support the compression of additional file formats and address some compatibility issues.

This behavior is unique to Akamai's Ion product and it requires the Adaptive Acceleration feature. Complete details are covered in Ion's documentation.
Updated 7 months ago