When you activate this setting, the exporter removes keys from objects on export if the plug-in determines that the animation has only one key. When two or more keys exist in the file, the keys are exported.
If you disable this option, the plug-in does not remove keys from the animation on export.
Sometimes, even though objects in a file contain no animation, they have a single key assigned to them for use as a locator. If you do not need these single keys in your file, you can reduce the file size by activating Remove single keys to discard them.