src/vs/workbench/services/themes/common/themeExtensionPoints.ts/ThemeRegistry/getMarketplaceThemes
class ThemeRegistry:	public getMarketplaceThemes(manifest: any, extensionLocation: URI, extensionData: ExtensionData): T[] {
		const themes = manifest?.contributes?.[this.themesExtPoint.name];
		if (Array.isArray(themes)) {
			return this.onThemes(extensionData, extensionLocation, themes);
		}
		return [];
	}