src/vs/workbench/services/themes/browser/productIconThemeData.ts/ProductIconThemeData/toStorage
class ProductIconThemeData:	toStorage(storageService: IStorageService) {
		const iconDefinitions = [];
		const iconFontDefinitions: { [id: string]: IconFontDefinition } = {};
		for (const entry of this.iconThemeDocument.iconDefinitions.entries()) {
			const font = entry[1].font;
			iconDefinitions.push({ id: entry[0], fontCharacter: entry[1].fontCharacter, fontId: font?.id });
			if (font && iconFontDefinitions[font.id] === undefined) {
				iconFontDefinitions[font.id] = IconFontDefinition.toJSONObject(font.definition);
			}
		}
		const data = JSON.stringify({
			id: this.id,
			label: this.label,
			description: this.description,
			settingsId: this.settingsId,
			styleSheetContent: this.styleSheetContent,
			watch: this.watch,
			extensionData: ExtensionData.toJSONObject(this.extensionData),
			iconDefinitions,
			iconFontDefinitions
		});
		storageService.store(ProductIconThemeData.STORAGE_KEY, data, StorageScope.PROFILE, StorageTarget.MACHINE);
	}