By default the https://github.com/Microsoft/vscode does not come with key:

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

on its https://github.com/Microsoft/vscode/blob/master/product.json file. That entry is required to install extensions from the marketplace as showed on:

1. https://stackoverflow.com/questions/37143536/no-extensions-found-when-running-visual-studio-code-from-source

Also there is this commits, where their developer putted the key:

1. b00945f
2. f1d0c1d

But sequentially removed it justifying:

Revert inadvertant change to product.json

Why they are removing it? Seems they are using it while developing, as we may see he let slip the line to the upper stream. Can I put it on my fork? Or I can only use it locally as they seem to be doing?

Related issues:

1. Menu license links to non Open Source license #60 Command "Extensions: Install Extension" missing when running vscode from source
2. Command "Extensions: Install Extension" missing when running vscode from source #2647 Command "Extensions: Install Extension" missing when running vscode from source
3. Can't see extensions or load via command line #28253 Can't see extensions or load via command line
4. How do I enable extensions in the extensions dir in OSS Dev mode #23831 How do I enable extensions in the extensions dir in OSS Dev mode
5. Add marketplace extension installation details vscode-wiki#30 Add marketplace extension installation details