Hints for xcas in main

Warnings

• asv-cid-desktopapp-is-not-rdns
  xcas.metainfo.xml:4 - xcas
  The component ID is not a reverse domain-name. Please update the ID to avoid future issues and be compatible with all AppStream implementations. You may also consider to update the name of the accompanying .desktop file to follow the latest version of the Desktop-Entry specification and use a rDNS name for it as well. In any case, do not forget to mention the new desktop-entry in a <launchable/> tag for this component to keep the application launchable from software centers and the .desktop file data associated with the metainfo data.
• asv-description-spurious-text
  xcas.metainfo.xml:41 -
  The description element contains raw text that is not in any paragraph or other permitted tag. This is not allowed and the additional text may be ignored by parsers or raise errors.
• asv-description-no-valid-content
  xcas.metainfo.xml:39 -
  The description element does not contain any valid content (paragraphs, enumerations, etc.).
• screenshot-download-error
  Error while downloading screenshot from 'https://www-fourier.univ-grenoble-alpes.fr/~parisse/giac/formel.png': Failed to download file: Operation too slow. Less than 5000 bytes/sec transferred the last 60 seconds
  This might be a temporary server issue, or the screenshot is no longer available.
• screenshot-download-error
  Error while downloading screenshot from 'https://www-fourier.univ-grenoble-alpes.fr/~parisse/giac/horner.png': Failed to download file: Operation too slow. Less than 5000 bytes/sec transferred the last 60 seconds
  This might be a temporary server issue, or the screenshot is no longer available.