Write to [email protected] for anything about the catalog: a missing system, a wrong license, an outdated link, a metric that looks off, or a question about how entries are compiled.
The fastest route is the "Add a system" button on the home page. It asks for the name and the official URL, and optionally the GitHub repository and the Figma library. Anything you add in the comment field — who maintains the system, which framework it targets, whether it is still active — saves a round of research and gets the entry published sooner.
The bug button in the footer of the home page sends the report with the page address attached. Leave an email in the form if you want an answer; without it the report is still read, there is just no way to reply.
If a metric or a license is wrong on your own system, say which entry and what it should be. Corrections to entries about your own product are applied first.