The mimemap file

mimemap specifies the file name extension to MIME type mappings.

For file names without an extension, or with an unknown one, the MIME type is optionally determined by inspecting the file contents. This is controlled by the usesystemfilecommand configuration variable. Depending on a compile time option, Recoll then either executes a system command, or uses the magic library.

On most platforms, and always on Windows, Recoll is built to use libmagic. Otherwise, the command used is either file or xdg-mime, and can be configured by setting the systemfilecommand variable.

All extension values in mimemap must be entered in lower case. File names extensions are lower-cased for comparison during indexing, meaning that an upper case mimemap entry will never be matched.

The mappings can be specified on a per-subtree basis, which may be useful in some cases. Example: okular notes have a .xml extension but should be handled specially, which is possible because they are usually all located in one place. Example:

[~/.kde/share/apps/okular/docdata]
.xml = application/x-okular-notes

See also the noContentSuffixes configuration variable, for specifying file name extensions for which no content indexing will be performed.