Devanagari long-e vowel sign

It marks a long schwa in a Devanagari transcription of Avestan.

A schwa is a neutral vowel; this mark distinguishes its long reading from the regular schwa marked by ॅ. It belongs to a Devanagari convention for writing the Avesta, not to Avestan's historical alphabet. Avestan is the language of Zoroastrian sacred texts and has a historical alphabet of its own.

The earliest documented printed example is in Kanga's Devanagari edition of the Avesta, in Yasna 41.4. The edition is dated 1962 and 1965, and a 2007 Unicode proposal reproduces the passage. A separate Unicode comment from 2007 says the mark can sit over ए for a word-initial long e.

How do I type ॕ?

Place it after the Devanagari character it marks.

As a combining mark, ॕ attaches to the base before it; in the documented convention it can sit over ए for an initial long e. Enter the base first, then insert ॕ with a Unicode-capable input method; the keystroke depends on your keyboard. A printed example, युजॕन्, shows it inside a word.

If it seems to disappear or sit out of place, the font may lack the shaping support needed to position it well. The text can still contain the intended mark even when a font renders it poorly.