OpenAPI 2.0 is not picking up the SpecLynx icon

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OpenAPI 2.0 is not picking up the SpecLynx icon. {} icon is still present.

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Ahh—got it. If your language is correctly applied but your icon disappears only for swagger.json, that’s the file icon theme stepping in.

VS Code decides the little file icon like this (highest → lowest):

1. Explicit filename rules from the active file icon theme (e.g., a theme that maps swagger.json to a special Swagger icon)
2. File extension rules from the icon theme
3. Language ID icon (from your extension’s contributes.languages[*].icon) as a fallback

So when the file is literally swagger.json, a lot of icon themes (or OpenAPI-related icon packs) have a filename mapping that overrides your language icon. That’s why your icon shows for other filenames but not this one.

What you can do

Quick checks

• Switch File Icon Theme to the built-in “Seti (Visual Studio Code)” or “Minimal” and reopen the file. If your icon shows, a different icon theme (or icon pack extension) is overriding swagger.json.
• If you want to keep your current theme, try renaming to something like my-swagger.json—you’ll see your language icon come back, confirming the filename rule is the culprit.

Options to fix / control it

1. Live with the theme’s filename icon
   This is by design: themes are user-controlled and allowed to win on specific filenames.

2. Ship your own file icon theme (guaranteed control—for users who select it)
   Contribute an icon theme that maps either your languageId or the specific filename to your icon:

   package.json

   {
     "contributes": {
       "iconThemes": [
         {
           "id": "myFileIcons",
           "label": "My File Icons",
           "path": "./icons/my-theme.json"
         }
       ]
     }
   }

   icons/my-theme.json

   {
     "iconDefinitions": {
       "_myLang": { "iconPath": "./myLang.svg" }
     },
     "languageIds": {
       "yourLanguageId": "_myLang"
     },
     "fileNames": {
       "swagger.json": "_myLang"
     }
   }

   Users who pick My File Icons will see your icon even for swagger.json.

3. Rely on your language icon where possible
   Make sure you’ve set it:

   {
     "contributes": {
       "languages": [
         {
           "id": "yourLanguageId",
           "aliases": ["Your Language"],
           "icon": {
             "light": "./icons/your-lang-light.svg",
             "dark": "./icons/your-lang-dark.svg"
           }
         }
       ]
     }
   }

   This covers cases where the icon theme doesn’t have a filename rule; but filename rules will still override it.

4. Add a subtle overlay instead of changing the icon
   If you want to mark swagger.json regardless of theme, use a FileDecorationProvider (badge/tooltip/color overlay) — decorations stack with any icon theme:

   vscode.window.registerFileDecorationProvider({
     onDidChangeFileDecorations: new vscode.EventEmitter<vscode.Uri | vscode.Uri[]>().event,
     provideFileDecoration(uri) {
       if (uri.fsPath.match(/(^|\/)swagger\.json$/i)) {
         return { badge: "S", tooltip: "Swagger file" };
       }
       return;
     }
   });

Bottom line

Nothing is wrong with your language. The active file icon theme has a special rule for swagger.json and that wins over your language’s icon. If you need your icon to appear for that exact filename, either provide an icon theme (and have users select it) or use a decoration overlay.