What ꬪ means
Read ꬪ as one syllable inside a Gumuz word. A font without it may show a box or replacement; Unicode’s chart drawing does not prescribe every font.
Ethiopic grew from South Arabian writing. South-Arabian-related inscriptions in Ethiopia and Eritrea date to the 8th/7th centuries BCE. Clear Ethiopic writing appears by the 2nd or 3rd century CE, with vowel marking by the 4th century. Those are script dates, not ꬪ. A 2009 proposal documents the extension in Gumuz books, including a 2003 New Testament; it notes that churches still published in Ethiopic while language groups officially chose Latin.
Don't confuse it with
4Questions people ask
1Why does ꬪ show as a box on some devices?
Because that device's fonts have no glyph for it. The character is still correct and still copies correctly — the box is a missing glyph, not a broken character.
How to type ꬪ
ꬪ\AB2ACodes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.