"No extensions found" when running Visual Studio Code from source

You can use code-marketplace extension in AUR to add microsoft marketplace registery in code OSS. This extension will installs a pacman hook that patches the file on every package update.

This can be fixed by adding following to product.json:

"extensionsGallery": {
    "serviceUrl": "https://marketplace.visualstudio.com/_apis/public/gallery",
    "cacheUrl": "https://vscode.blob.core.windows.net/gallery/index",
    "itemUrl": "https://marketplace.visualstudio.com/items"
}

(This is can also be fixed by copying product.json from an official build (in the .zip archvie, product.json is under resources/app) which contains above lines).

More information: https://github.com/Microsoft/vscode/issues/1557