A question about electrons?

Question

Is there any circumstantial evidence that the electron has a structure. Did any one conduct any experiment to prove it?

Answer 1

In the Standard Model, the electron is a lepton and it is not supposed to have a "structure", but it may have properties.

The baryons, like the proton, are supposed to be made of quarks, so they do have a  internal "structure".

Remark. These objects are very remote from our daily experience.

For calculation and visualization, we represent a proton like a tiny shiny ball. But a proton does not have an interior  or an outer layer: it is more like a bunch of "bindings" between positions in space.