Select: 
Category
All
Graphic ambiguousness
Interpretations within context
Differences between sources
Editorial revisions
Corrections & alterations
Source & stylistic information
Pitch
All
Pitch
Rhythm
Slurs
Articulation, Accents, Hairpins
Verbal indications
Pedalling
Fingering
Ornaments
Shorthand & other
Importance
All
Important
Main


Pitch

b. 15

composition: Op. 2, Variations, complete

d2 in AsI

d2 in A (→GEFE,EE,FESB)

..

Taking into account the three previous similar phrases in this bar and d2 in AsI, one could assume an oversight of a  in A. However, it seems more likely that Chopin consciously changed the pitch of this note:

  • Chopin would often omit accidentals to notes belonging to the current key; however, he would rarely overlook an accidental supposed to define the alteration (only a few times in his entire oeuvre);
  • Chopin did not correct the possible mistake while proofreading FE, despite the fact that he changed slurs in this very bar.

category imprint: Differences between sources; Corrections & alterations

issues: Main-line changes

b. 19

composition: Op. 2, Variations, complete

e3-g3 in sources, literal reading

e3-g3 suggested by the editors

..

Even though none of the sources features an accidental to the top note of the last semiquaver, the use of g3 is much more likely, considering the melodic and harmonic context. Overlooked accidentals in such situations are one of Chopin's most frequent mistakes, cf., e.g. the Etude in F minor, Op. 25 No. 2, b. 4 or the Impromtu in A, Op. 29, b. 3 and 71. 

category imprint: Differences between sources

issues: Omissions to cancel alteration , Errors of A

b. 19

composition: Op. 2, Variations, complete

Repeated thirds in #ApI

Single notes in A (→GEFE,EE,FESB)

category imprint: Differences between sources; Corrections & alterations; Source & stylistic information

issues: Chopin's hesitations , Main-line changes

b. 20

composition: Op. 2, Variations, complete

c in A, FE & GE2 (→GE3,FESB)

e in GE1 (→EE)

..

The version of GE1 (→EE) must be a Terzverschreibung, corrected in GE2 (→GE3,FESB) and in FE1, probably by Chopin.

category imprint: Differences between sources

issues: Errors in GE , GE revisions , Authentic corrections of FE

b. 25

composition: Op. 2, Variations, complete

e in A, FE, FESB & GE3

e in GE1 (→GE2,EE)

..

The version of GE1 (→GE2,EE), featuring e, is almost certainly erroneous – there are no traces of removal of the , despite the numerous traces of corrections visible in this and adjacent bars (very clear in GE2) related to the misinterpreted L.H.-part rhythm. The overlooked  was added by FE and FESB.
EE revised the version of GE1 by removing the  to e in the 2nd half of the bar, unnecessary due to the missing  at the beginning of the bar.

category imprint: Differences between sources

issues: EE revisions , Errors in GE , Authentic corrections of FE , FE revisions