src/vs/workbench/contrib/terminal/common/environmentVariableService.ts/EnvironmentVariableService/_persistCollections
class EnvironmentVariableService:	protected _persistCollections(): void {
		const collectionsJson: ISerializableExtensionEnvironmentVariableCollection[] = [];
		this.collections.forEach((collection, extensionIdentifier) => {
			if (collection.persistent) {
				collectionsJson.push({
					extensionIdentifier,
					collection: serializeEnvironmentVariableCollection(this.collections.get(extensionIdentifier)!.map)
				});
			}
		});
		const stringifiedJson = JSON.stringify(collectionsJson);
		this._storageService.store(TerminalStorageKeys.EnvironmentVariableCollections, stringifiedJson, StorageScope.WORKSPACE, StorageTarget.MACHINE);
	}