Hints for d2x-rebirth in non-free

Hints

• asv-cid-contains-hyphen
  :3 - io.github.dxx_rebirth.dxx_rebirth.d2x-rebirth
  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 (`_`).
• asv-unknown-tag
  :5 - developer
  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.