Sketchnote Text, Italic and Bold were built from hundreds of hand-drawn glyphs, and variations on glyphs . These added characters allowed Delve to create Contextual Alternates — multiple variations on each character which help recreate variations in handwriting and can be accessed with tools that support this OpenType feature, like InDesign.
(via The Sketchnote Typeface – Rohdesign – Designer Mike Rohde )