20 files declare their use of BackupFileReadableInterface in Backup and Migrate 8.4

ArchiveReaderInterface.php in lib/backup_migrate_core/src/Service/ArchiveReaderInterface.php

ArchiverInterface.php in lib/backup_migrate_core/src/Service/ArchiverInterface.php

BrowserDownloadDestination.php in lib/backup_migrate_core/src/Destination/BrowserDownloadDestination.php

CompressionFilter.php in lib/backup_migrate_core/src/Filter/CompressionFilter.php

DebugDestination.php in lib/backup_migrate_core/src/Destination/DebugDestination.php

DestinationBase.php in lib/backup_migrate_core/src/Destination/DestinationBase.php

DirectoryDestination.php in lib/backup_migrate_core/src/Destination/DirectoryDestination.php

DrupalBrowserDownloadDestination.php in src/Destination/DrupalBrowserDownloadDestination.php

DrupalDirectoryDestination.php in src/Destination/DrupalDirectoryDestination.php

DrupalEncrypt.php in src/Filter/DrupalEncrypt.php

DrupalMySQLiSource.php in src/Source/DrupalMySQLiSource.php

DrupalSiteArchiveSource.php in src/Source/DrupalSiteArchiveSource.php

DrupalUtils.php in src/Filter/DrupalUtils.php

FileDirectorySource.php in lib/backup_migrate_core/src/Source/FileDirectorySource.php

FileNamer.php in lib/backup_migrate_core/src/Filter/FileNamer.php

MySQLiSource.php in lib/backup_migrate_core/src/Source/MySQLiSource.php

SourceInterface.php in lib/backup_migrate_core/src/Source/SourceInterface.php

StreamDestination.php in lib/backup_migrate_core/src/Destination/StreamDestination.php

TarArchiveReader.php in lib/backup_migrate_core/src/Service/TarArchiveReader.php

WritableDestinationInterface.php in lib/backup_migrate_core/src/Destination/WritableDestinationInterface.php