U+10A66 Old South Arabian Letter Shin

The Wikipedia has the following information about this codepoint:

The Ancient South Arabian script (Old South Arabian: 𐩣𐩯𐩬𐩵 ms³nd; modern Arabic: الْمُسْنَد musnad) branched from the Proto-Sinaitic script in about the late 2nd millennium BCE. It was used for writing the Old South Arabian languages Sabaic, Qatabanic, Hadramautic, Minaean Hasaitic, and Geʽez in Dʿmt. The earliest instances of the Ancient South Arabian script are painted pottery sherds from Raybun in Hadhramaut in Yemen, which are dated to the late 2nd millennium BCE. There are no letters for vowels, though some can be indicated via matres lectionis.

Its mature form was reached around 800 BCE and its use continued until the 6th century CE, including Ancient North Arabian inscriptions in variants of the alphabet, when it was displaced by the Arabic alphabet. In Eritrea and Ethiopia, it evolved later into the Geʽez script, which, with added symbols throughout the centuries, has been used to write Amharic, Tigrinya and Tigre, as well as other languages (including various Semitic, Cushitic, Omotic, and Nilo-Saharan languages).