Hints for cura in main

Hints

• asv-desktop-app-launchable-omitted
  com.ultimaker.cura.appdata.xml -
  This `desktop-application` component has no `desktop-id` launchable tag, however it contains all the necessary information to display the application. The omission of the launchable entry means that this application can not be launched directly from installers or software centers. If this is intended, this information can be ignored, otherwise it is strongly recommended to add a launchable tag as well.
• asv-content-rating-missing
  com.ultimaker.cura.appdata.xml -
  This component has no `content_rating` tag to provide age rating information. You can generate the tag data online by answering a few questions at https://hughsie.github.io/oars/
• asv-developer-info-missing
  com.ultimaker.cura.appdata.xml -
  This component contains no `developer` element with information about its author.