U+02B1 Modifier Letter Small H with Hook

The Wikipedia has the following information about this codepoint:

Breathy voice (also called murmured voice, whispery voice, soughing and susurration) is a phonation in which the vocal folds vibrate, as they do in normal (modal) voicing, but are adjusted to let more air escape which produces a sighing-like sound. A simple breathy phonation, [ɦ] (not actually a fricative consonant, as a literal reading of the IPA chart would suggest), can sometimes be heard as an allophone of English /h/ between vowels, such as in the word behind, for some speakers.

In the context of the Indo-Aryan languages like Sanskrit and Hindi and comparative Indo-European studies, breathy consonants are often called voiced aspirated, as in the Hindi and Sanskrit stops normally denoted bh, dh, ḍh, jh, and gh and the reconstructed Proto-Indo-European phonemes bʰ,dʰ,ǵʰ,gʰ,gʷʰ. From an articulatory perspective, that terminology is inaccurate, as breathy voice is a different type of phonation from aspiration. However, breathy and aspirated stops are acoustically similar in that in both cases there is a delay in the onset of full voicing. In the history of several languages, like Greek and some varieties of Chinese, breathy stops have developed into aspirated stops.