Breakpoints in custom theme not showing in the "group breakpoints" field

I'm having a problem that i simply can't find how to resolve it. I've created a custom theme based on the "claro" from drupal core. Then I've installed the modules Breakpoints + Responsive Image.

I've renamed the theme as "nescau", and created a new breakpoints file. "nescau.breakpoints.yml". I've created 2 breakpoints: "nescau.mobile", and "nescau.desktop" to test the module.

The problem is when I go this url:

http://nescaumeeg/admin/config/media/responsive-image-style/add

so I can add image styles for the breakpoints, the nescau.breakpoints doesn't show in the field "group".

In the image example, there should be a "nescau" inside that field, so I can choose an image style for each breakpoint.

I've tried searching on the web, but found nothing. I'll be glad if someone could help me.

EDIT

I'm using a custom theme that has the base theme as "claro" from core.

This is the breakpoints file.

nescau.mobile:
  label: mobile
  mediaQuery: '(min-width: 0px)'
  weight: 0
  multipliers:
    - 1x
    - 2x
nescau.desktop:
  label: desktop
  mediaQuery: 'all and (min-width: 800px)'
  weight: 1
  multipliers:
    - 1x
    - 2x