src/vs/workbench/contrib/extensions/browser/extensionsWorkbenchService.ts/ExtensionsWorkbenchService/onOpenExtensionUrl
class ExtensionsWorkbenchService:	private onOpenExtensionUrl(uri: URI): void {
		const match = /^extension\/([^/]+)$/.exec(uri.path);

		if (!match) {
			return;
		}

		const extensionId = match[1];

		this.queryLocal().then(local => {
			const extension = local.filter(local => areSameExtensions(local.identifier, { id: extensionId }))[0];

			if (extension) {
				return this.hostService.focus()
					.then(() => this.open(extension));
			}
			return this.queryGallery({ names: [extensionId], source: 'uri' }, CancellationToken.None).then(result => {
				if (result.total < 1) {
					return Promise.resolve(null);
				}

				const extension = result.firstPage[0];

				return this.hostService.focus().then(() => {
					return this.open(extension);
				});
			});
		}).then(undefined, error => this.onError(error));
	}