U+0258 Latin Small Letter Reversed E

The Wikipedia has the following information about this codepoint:

The close-mid central unrounded vowel, or high-mid central unrounded vowel, is a type of vowel sound used in some spoken languages. The symbol in the International Phonetic Alphabet that represents this sound is ⟨ɘ⟩. This is a mirrored letter e and should not be confused with the schwa ⟨ə⟩, which is a turned e. It was added to the IPA in 1993; before that, this vowel was transcribed ⟨ë⟩ (Latin small letter e with diaeresis, not Cyrillic small letter yo). Certain older sources transcribe this vowel ⟨ɤ̈⟩.

The ⟨ɘ⟩ letter may be used with a lowering diacritic ⟨ɘ̞⟩, to denote the mid central unrounded vowel.

Conversely, ⟨ə⟩, the symbol for the mid central vowel may be used with a raising diacritic ⟨ə̝⟩ to denote the close-mid central unrounded vowel, although that is more accurately written with an additional unrounding diacritic ⟨ə̝͑⟩ to explicitly denote the lack of rounding (the canonical value of IPA ⟨ə⟩ is undefined for rounding).