API reference / Common / Engine types / TextLigatures
Interface: TextLigatures
The optional ligatures a span is set with (w14:ligatures, MS-DOCX 2.6.1.17) — four independent kinds, each the OpenType feature the shaper turns on. docx-only; DrawingML has no counterpart. ST_Ligatures (MS-DOCX 2.6.4.3) spells every combination of the four as one value: standardContextual is standard and contextual, none all four off.
A span whose chain specifies none is set with none — the default — and PowerPoint, with nothing to specify, forms none either. Required ligatures (rlig) are not among the kinds: they are the script's, and always formed.