Hints for xfce4-clipman in universe

xfce4-clipman.desktop ⚙ amd64

desktop-entry-category-invalid
The category name TrayIcon is invalid. The software can not be shown in this category.
asv-cid-desktopapp-is-not-rdns
xfce4-clipman.appdata.xml:3 - xfce4-clipman.desktop
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-unknown-tag
xfce4-clipman.appdata.xml:65 - updatecontact
Found invalid tag. Non-standard tags should be prefixed with `x-`. AppStream also provides the <custom/> tag to add arbitrary custom data to metainfo files. This tag is read by AppStream libraries and may be useful instead of defining new custom toplevel or `x-`-prefixed tags if you just want to add custom data to a metainfo file.
asv-screenshot-media-url-not-secure
xfce4-clipman.appdata.xml:57 - http://docs.xfce.org/_media/extra/clipman/clipman-menu.png
Consider using a secure (HTTPS) URL to reference this screenshot image or video.
asv-cid-contains-hyphen
xfce4-clipman.appdata.xml:3 - xfce4-clipman.desktop
The component ID contains a hyphen/minus. Using a hyphen is strongly discouraged, to improve interoperability with other tools such as D-Bus. A good option is to replace any hyphens with underscores (`_`).