Recoll was designed not to require a permanent daemon; on Linux systems, it can make use of inotify. Recoll updates its index at designed intervals (for example, through cronjobs), but if desired, the indexing task can run as a file-system monitoring daemon for real-time index updates.[4]
Maildir, MH, and mailbox (Mozilla, Thunderbird, and Evolution). Evolution requires .cache to be removed from the skippedNames list in the GUI Indexing preferences/Local Parameters/ Pane to index local copies of IMAP mail.
Mimehtml web archive format (support based on the mail filter).
All the following need Python 3:
Dia diagrams.
Excel and PowerPoint (pre-open XML).
Tar archives. Tar file indexing is disabled by default given that tar archives don't typically contain the kind of documents that people search for, so it needs to be enabled explicitly with "[index]" or "application/x-tar=execm rcltar" in a $HOME/.recoll/mimeconf file.
Zip archives.
Konqueror web archive format (uses the tarfile Python standard library module).