Dear @serum
Unsure sorry but these links may provide some help 🌝
http://laythemeforum.com:4567/topic/917/activate-styllistic-sets/6
http://laythemeforum.com:4567/topic/6094/variable-font-can-be-used/6
http://laythemeforum.com:4567/topic/6476/font-encoded-in-base64/4
http://laythemeforum.com:4567/topic/6206/webfont-issue-2-fonts-working-fine-3rd-one-doesn-t
Best
Richard