Based on the url, Tentacle will automatically select the right icon for the link. If you want to override the icon, you can do so by adding the icon attribute to the link. Tentacle supports all Octoicons and more. For combability with Backstage, some of the Material Icons are mapped to Octoicons.

catalog-info.yaml
apiVersion: backstage.io/v1alpha1
kind: Component
metadata:
  name: artist-service
  links:
    - url: https://docs.example.com
      title: Documentation
      icon: book
spec:
  type: service
  lifecycle: production
  owner: team-awesome