[BUG] extraKnownMarketplaces key doesn't work as alias - must match marketplace.json name

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report
• [x] I am using the latest version of Claude Code

What's Wrong?

The key in extraKnownMarketplaces doesn't work as an alias. It has to exactly match the name field in the marketplace's marketplace.json, or the plugin fails to load with "Plugin not found in marketplace".

What Should Happen?

According to the docs, the key should work as a local alias independent of the marketplace.json name.

Error Messages/Logs

Plugin Errors

   ❯ dev-browser@dev-browser
      Plugin 'dev-browser' not found in marketplace 'dev-browser'
      → Plugin may not exist in marketplace 'dev-browser'

Steps to Reproduce

1. Add a GitHub marketplace with a custom key that differs from the repo's marketplace.json name:

{
  "extraKnownMarketplaces": {
    "my-alias": {
      "source": {
        "source": "github",
        "repo": "SawyerHood/dev-browser"
      }
    }
  },
  "enabledPlugins": {
    "dev-browser@my-alias": true
  }
}

1. The repo's marketplace.json has "name": "dev-browser-marketplace"

1. Restart Claude Code - plugin fails to load

1. Change the key to match the marketplace.json name (dev-browser-marketplace) and it works

Is this a regression?

I don't know

Claude Code Version

2.1.1 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

VS Code integrated terminal

Additional Information

The marketplace was properly downloaded to ~/.claude/plugins/marketplaces/dev-browser-marketplace/ - the issue is specifically that the alias key is ignored and the marketplace.json name is used instead.