ताण्ड्य महाब्राह्मण / पञ्चविंश ब्राह्मण (सायण भाष्य एवं चिन्नस्वामी शास्त्री टीका सहित)

with a horizontal line like थ or त्स?
Wait, in old prints त्स्या is printed as त् + स + य or र्त्स्या:
Wait, does it have a repha on top? Yes, a hook र्.
Below the hook: त् and थ? No, र्थ्या! It looks very much like मर्थ्या or मर्त्स्या!
Wait, let's look at र्थ्या: the letter has र् on top, and थ्य with ा! But wait, is it थ्या or त्स्या?
Look at त्स्नमवदाय in line 5: त्स्न has त् above स with a loop.
Here, under the repha, there is a round loop with a vertical line: that's थ! Wait, does थ have a vertical line? थ्या: थ attached to य with a central dot/circle. But notice the line through the middle: थ often has a line or is round. But wait, अमर्त्स्याः vs अमर्त्याः!
Wait, in Vedic Sanskrit, is it अमर्त्या or अमर्त्स्या?
"महन् मेऽद्य अमर्त्या व्रतं" -> "अमर्त्याः" (vocative