अणुभाष्य (महाप्रभु वल्लभाचार्य - शुद्धाद्वैत वेदान्त ब्रह्मसूत्र महाभाष्य प्रकाश टीका सहित)

'? That's a quotation mark!
Look: बृहदारण्यकस्थ'एतद्वै - the 'प' looking thing is actually an opening single quote: ‘ or "!
In Indian typography, opening quotes are often like ‘ (raised 6 or comma).
Look at line 1: श्रुतिस्थ'स्यात्मान' -> opening quote!
Line 4: 'अमृतस्य -> opening quote!
Line 5: 'लक्ष्यं -> opening quote!
Line 14: 'तमेवैकं -> opening quote!
Line 16: 'द्वा सुपर्णा' -> opening quote!
Line 21: 'यो वै भूमा -> opening quote!
Line 23: 'स एवाधस्तादि' -> opening quote!
Line 25: 'नान्यत्पश्यती' -> opening quote!
Line 29: 'एतद्वै -> opening quote! Look at the mark before 'ए': it's a quote mark! But wait, is it 'ए' or 'प्रे'? The letter is clearly 'ए': 'एतद्वै तदक्षरं गार्गि'!
In Brihadaranyaka 3.8.8: "एतद्वै तदक्षरं गार्गि ब्राह्मणा अभिवदन्त्यस्थूलमनण्वह्रस्वमदीर्घम्..."
So it is definitely 'एतद्वै तदक्षरं गार्गी'तिवाक्यं!

Line 30: