How to switch between hollow/filled fonts ?

Hello,
I've used my forerunner 955's included fonts with success, both fixed and scalables, but I can't see how to render text using hollow characters, with transparent filling and only the external stroke coloured, as shown on my factory built watch faces.

Is Garmin using another font for that purpose ? If so, why is it not available as are the other fonts ?

Thanks for your help.

Nicolas.