electric-layout-rules is a variable defined in `electric.el'.
Its value is

List of rules saying where to automatically insert newlines.

Each rule has the form (CHAR . WHERE) where CHAR is the char that
was just inserted and WHERE specifies where to insert newlines
and can be: nil, `before', `after', `around', `after-stay', or a
function of no arguments that returns one of those symbols.

The symbols specify where in relation to CHAR the newline
character(s) should be inserted. `after-stay' means insert a
newline after CHAR but stay in the same place.