A
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from 1st third in 
All minor differences in the range of this sign appearing in the editions are certainly of random nature. In this case, the sign certainly means a "very long" accent, hence shifts both in GE1 and GE2 distorted its sense.
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category imprint: Differences between sources
issues: Inaccuracies in GE, Inaccuracies in FE, GE revisions
notation: Articulation, Accents, Hairpins