Where are Shabbos/Yom Tov prayers in the Siddur?

The Shabbos and Yom Tov prayers are not included in the Siddur in accordance with Orthodox Halachic ruling that electronic devices may not be used on Shabbos and Yom Tov.

The digital Siddur is a Weekday Siddur, and therefore only includes weekday prayers. This is also why on Friday, Maariv will be shaded out, and will not be accessible.