LaTeX2e is, if I don't make any mistake, the successor of LaTeX 2.09, and was published in 1994 (I was 4 year old !). My question is very simple : why has called it LaTeX2e and not, for example LaTeX 2.10 ?
As Frank says in his interview
Although LaTeX2e already addressed most, if not all, of the deficiencies identified in the first decade of LaTeX 2.09 use, it was originally thought that LaTeX2e would only be an intermediate step towards a LaTeX 3 version
So that really is the name 2-e or 2-epsilon, a small step towards 3.