The new “Stylize” filter doesn’t work as expected. It requires at least two layers to be present in the original, but even if they do exist in the original, the error message persists.
Moreover, the presets are not included in the Plug-in. One needs an existing internet connection to use (and apparently download) one of the preset images. This can be frustrating if you need one while on a train.
It would also help to add a feature to add a new image as a preset from the local file system or the web via a file selector.
Tested with the G’MIC plug-in 2.6.3 for GIMP 2.10.10 on Windows 10.