Find = \[([0-9,]@)\]
Replace = \1

If I'm understanding how you did this, character-by-character...
\[ ' literal open bracket
( ' beginning of a group?
[0-9] ' any single digit, 0-9,
1 or more times,
, ' Not sure how it knows to use the comma 0 or more times? But that's what it's doing.
) ' end group
@ look for the pattern [0-9], 1 or more times?
\] ' literal close bracket.

Replace = \1
What does this mean? It is removing the square brackets, but how does it know that?
I'm trying to understand how this all works as we may also want to allow for periods in the brackets, like [2,3.4]