CallerConnect bundles three Google Fonts, each under the SIL Open Font License 1.1
(free to use, embed, and redistribute):

  Rubik             https://fonts.google.com/specimen/Rubik
  Spline Sans       https://fonts.google.com/specimen/Spline+Sans
  Spline Sans Mono  https://fonts.google.com/specimen/Spline+Sans+Mono

Full licence text: https://openfontlicense.org