In AI the notation of the part of the R.H. is unclear in this bar. Chopin certainly performed corrections in it, yet it is unclear, which version is the last one. According to us, it is most natural to assume that Chopin strived for the version which he then eventually deemed as the best, while the remaining ones – written out with notes – are earlier:
and 
. Therefore, it is the sign defining this bar as repetition of the previous one that we consider to be written as the last one. See also the note on abbreviations in the L.H.
Compare the passage in the sources»
category imprint: Differences between sources; Corrections & alterations; Source & stylistic information
issues: Abbreviated notation of A
notation: Pitch