src/vs/workbench/services/workingCopy/common/workingCopyBackupService.ts/NativeWorkingCopyBackupServiceImpl/discardBackups
class NativeWorkingCopyBackupServiceImpl:	async discardBackups(filter?: { except: IWorkingCopyIdentifier[] }): Promise<void> {
		const model = await this.ready;

		// Discard all but some backups
		const except = filter?.except;
		if (Array.isArray(except) && except.length > 0) {
			const exceptMap = new ResourceMap<boolean>();
			for (const exceptWorkingCopy of except) {
				exceptMap.set(this.toBackupResource(exceptWorkingCopy), true);
			}

			await Promises.settled(model.get().map(async backupResource => {
				if (!exceptMap.has(backupResource)) {
					await this.doDiscardBackup(backupResource);
				}
			}));
		}

		// Discard all backups
		else {
			await this.deleteIgnoreFileNotFound(this.backupWorkspaceHome);

			model.clear();
		}
	}