वैयाकरण सिद्धान्त कौमुदी (भट्टोजि दीक्षित - बालमनोरमा व तत्त्वबोधिनी टीका सम्पूर्ण पूर्वार्ध)

or ᳵ or ≍).
Wait, in Unicode, Jihvamuliya is U+1CF5 (ᳵ) or U+0CF1 / U+1CF2.
Let's see how it's printed:
It is ‘ᳵकौ जिह्वामूले'!
Wait, could it be represented as ‘ᳵकौ or ‘≍कौ?
Let's look closely at the glyph:
It's a cross with curls at the top and bottom: indeed the Ardhavisarga / Jihvamuliya symbol!
In Unicode Devanagari: U+1CF5 is ᳵ (VEDIC SIGN ARDHAVISARGA).
Or U+1CF2 ᳲ (VEDIC SIGN ARDHAVISARGA).
Let's use ᳵकौ or ≍कौ. ᳵकौ is standard Devanagari Unicode.

Let's read line 6 of footnotes (our L19):
मूलीयक्वर्गौ जिह्वामूलस्थानकौ' इत्यर्थकेन 'जिह्वामूले तु कुः प्रोक्तः' इति पाणिनीयत्वेन प्रसिद्ध्या
Wait, "जिह्वामूलीयक्वर्गौ":
Look at the bold text:
मूलीयक्वर्गौ जिह्वामूलस्थानकौ'
Wait, `जिह्