What ꣫ means
It attaches to a syllable; it is not a vowel.
꣫ follows the syllable it modifies and is rendered above it. Böhtlingk and Roth’s St. Petersburg Sanskrit-English lexicon records it for udātta, the raised-pitch accent. In the Sāmaveda Saṃhitā, a Vedic chant collection, it follows a small raised 2 and marks the first of two udātta (raised-pitch) syllables before an anudātta (unraised-pitch) one.
Specialist Vedic notation for marking chant pitch.
Do not mistake it for the everyday vowel उ; ꣫ marks Vedic pitch.
Don't confuse it with
4Questions people ask
1Why does ꣫ 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 ꣫
꣫\A8EBCodes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.