Tayt writes an ejective t and continues the Semitic consonant behind the Hebrew teth, the Syriac teth and the emphatic ta of Arabic. It is the ejective partner of tawe, and the pair is inherited.
The relations recorded on this page and on the other twenty-five Ge'ez letters run sideways, to Hebrew, Syriac and Arabic, and never upwards. That is a limitation of the atlas rather than a claim about the script. The parent of the fidel is the Ancient South Arabian script, the monumental hand of the inscriptions of Saba, Qataban, Hadramawt and Main, and the atlas does not hold it as an alphabet. Until it does, a Ge'ez letter cannot be linked to the sign it actually descends from, only to the cousins that descend from a common ancestor further back.
The distinction matters because the two kinds of relation say different things. Ge'ez did not take its letters from Hebrew or from Arabic, and a chart that pairs them can be read as though it had. What the pairings record is common inheritance. The descent, the thing that would justify a relation pointing upwards, runs through a script of the Arabian peninsula that crossed the Red Sea and then, in Aksumite Ethiopia, was rebuilt into something its parent would not recognise.