Recoll is a cross-platform desktop search tool able to index nearly anything included inside nested files. From their website: "Recoll will index an MS-Word document stored as an attachment to an e-mail message inside a Thunderbird folder archived in a Zip file." Supported formats include HTML, OpenOffice, Microsoft Office, Office XML, PDF, WordPerfect, PostScript, TeX, and many others. Searches can be performed locally with either a graphical or a command-line search utility. Remote searches can also be performed using Recoll's web-based user interface. Documents matching a search can then be downloaded locally from the results page. Recoll for Windows can be downloaded from the website. For macOS, it is available through via MacPorts. For Linux, most distributions include a Recoll package. Recoll is a free software, licensed under the GNU General Public License, with source code available via the website.