In Jain Dharma, there isn’t a standard festival or observance specifically known as “28 Ananth Chaturdashi.” Anant Chaturdashi is primarily a Hindu observance, and Jain calendars may mention various days for personal puja or for honoring deities in a way that differs from Hindu practices, but there is no universal Jain festival tied to the date “28th” of a month.

If you can share the exact Jain context you saw ( Digambar or Shwetambar tradition, or a particular temple/region), I can give a more precise Jain interpretation. You can also read a Jain-focused explanation here