muCommander is a cross-platform file manager with a dual-pane interface that features support for FTP, SFTP, SMB, NFS, HTTP, Amazon S3, Hadoop HDFS, Bonjour/Zeroconf, email attachments, archives in many formats (including Zip, RAR, 7z, GZip, Tar, Bzip2, ISO, NRG, AR, Deb, and LST), bookmarks, credential management, themes, multiple windows, full keyboard control, and many configuration options. It is available in 23 languages.
KFile-Cert is a kfile-plugin for KDE. It offers detailed information on X.509 certificate files, which often have extensions .cer, .crt, or .pem. The information is displayed in the file properties dialog box, Konqueror pop-up file tips, and in Konqueror info list view. The information includes certificate subject, issuer, validity term, and status.