2nd movement of Beethoven's sonata Op. 49, No. 2. Bar 7. One edition seems to show two sets of fingering numbers: 4-3-2, and 4-4-2? What does it mean?
Your example and a few others showing multiple sets of fingerings.
...shows fingering alternatives.
Sometimes you see this in technique manuals...
...in that example the "German, English, French" labels help show the stacked up numbers are rows of alternate fingerings.
Also, multiple sets can be shows not so much as alternate fingers, but to give the meaning more of you should be able to do this movement with all digit combinations...
Fairly common is fingerings above and below notes on a single staff...
...in that example, the
LH markings make clear the two sets of numbers are for right hand and left hand instead of taking up more page space with a grand staff. That's really about simplifying the printed page.
Stacked fingering numbers are also used for chords or playing double notes in one hand...
Clearly, they're options. The idea of using the same finger to play a black key and the adjacent white key either up or down, is one technique that piano players have developed and particularly here, where the two notes are marked as slurred, it's an easy option. Not necessarily a necessity, as there's enough fingers left using even the top fingering, to land on G with the thumb, especially when the next note is only up by a third.
A typical convention for multiple sets of fingerings is that the upper fingering is the musically preferable version while the lower version is more accessible. Now my experience is from playing the violin where this quite commonly corresponds to the top version assigning phrases better to the different strings while the bottom version tends to focus on using "simpler" positions (according to the order in which learners tend to acquire and utilise positions and their changes).
I don't know whether there are similar semi-objective measures of difficulty vs musicality on the piano or whether there is not really a similar division and this is just an offer of alternatives, possibly related to hand size.
Interestingly, in Beethoven sonatas, the alternative fingerings are often his own suggestions.
I used the Henle edition when I was studying them, and they put italic numbers for Beethoven's suggestions. I don't remember whether your example is one of Beethoven's suggestions, but I suspect that it is.
Like Beethoven's pedal markings, his fingering suggestions have to be taken with a grain of salt, because his piano was very different from the ones we have at present. The notes don't last as long (so some long pedal markings get muddy on a modern piano), and the action is lighter, so some fingerings won't work well on a modern piano.