I used the theme generator of angular material m3 (v18). The generated file look like this:

$_palettes: (
  primary: (
    0: #000000,
    10: #001a43,
    20: #002d6c,
...

$_rest: (
  secondary: map.get($_palettes, secondary),
  neutral: map.get($_palettes, neutral),
  neutral-variant: map.get($_palettes,  neutral-variant),
  error: map.get($_palettes, error),
);
$_primary: map.merge(map.get($_palettes, primary), $_rest);
$_tertiary: map.merge(map.get($_palettes, tertiary), $_rest);

$light-theme: mat.define-theme((
  color: (
    theme-type: light,
    primary: $_primary,
    tertiary: $_tertiary,
    // use-system-variables: true,
  ),
  typography: (
    plain-family: 'Roboto, sans-serif',
    brand-family: 'Roboto, sans-serif',
    // use-system-variables: true,
  ),
));

Now I have some questions about the generated code:

1. _primary and _tertiary both contains secondary, neutral and error. This is assigned to the color. Why can’t I assign secondary directly?
2. Is there a place inside the theme where I can store custom colors which doesn’t belong to a palette? As far as I understand, palettes are supposed to be a range of colors with different shade.
3. In m2 it was possible to set the mat-typography class to body, so all elements used the correct font-family. Not sure why this has been removed. Is there something similar to make sure, elements like h2, h3… use the font-family which I assigned in typography in theme?