In the main text we add a cautionary 
before f
2. In analogous b. 493 the accidental is present in A and all the remaining sources. Moreover, Chopin probably hesitated in that respect, since the crossing-out visible there probably concerns the before that note, which means that it must have been entered twice.
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category imprint: Differences between sources; Editorial revisions; Source & stylistic information
issues: Chopin's hesitations, GE revisions, Cautionary accidentals, Deletions in A
notation: Pitch