Bibfilex is software to create and manage archives of bibliographical items (books, articles, etc.) according to Biblatex structure and rules. It is far less advanced than other bibliographic managers like JabRef, and allows only a few customizations. Its strength is speed and lightness, especially when used with many items. It uses SQLite as a database. It can store the items according to each of the entry types described in the Biblatex manual (book, article, etc.), import the content of a file in Biblatex format (like a JabRef database, a Mendeley BibTex exported file, or a Google Books BibTex downloaded file), export data to a Biblatex file (like a JabRef database), locate an item just typing its author name, title, etc. filter the items by selecting a keyword in a list, filter the items according to three different conditions (or to manually modify the SQL statement of the filter to make it more suitable or complex) or according to the \cite commands contained within a Latex document, associate various attachments (files of every kind) with each item, activate autocompletion of data in each field with “Ctrl + Space”, automatically create unique BibTex keys according to a pattern defined by the user, and specify the fields (columns) shown in the grid view of the data. It is also possible to replace the \cite and \printbibliography commands in a Latex document with extended citations and bibliography, which are composed according to a user-defined pattern, to export the Latex file in other formats more easily.
QueryFS is a FUSE-based virtual filesystem that is based on queries. There are plugins to parse various query syntaxes and each query creates a virtual directory. Currently the most elaborate query language is SQL-based; you can either provide access to data stored in an SQL database, or keep an index of files in the SQL database and generate search directories with symlinks to found files. QueryFS and its SQL2 query DSL fully support creation of refinable searches: for example, the author has an index of downloaded email files; one can see all the distinct senders registered in the DB and then go into a directory of one sender and see all accounts that ever received an email from this sender.
Jaro Mail is an integrated suite of interoperable tools for GNU/Linux and Apple/OS X to manage email communication in a private way, without relying on online services (in fact, encouraging users to store email locally). It mainly features a system for mailinglist filtering, address-book integrated whitelisting, and long-term email storage and archiving with functions for fast search and usage statistics. It makes internal use of customized versions of popular Unix tools like Mutt, Fetchmail, Procmail, Mairix, and Msmtp.
exceptions4c is a tiny, portable framework that brings the power of exceptions to your C applications. It provides a simple set of keywords (macros, actually) which map the semantics of exception handling you're probably already used to: try, catch, finally, throw. You can write try/catch/finally blocks just as if you were coding in Java. This way you will never have to deal again with boring error codes, or check return values every time you call a function.
Calligra is an integrated suite of applications that cover office, creative, and management needs. It offers applications on both desktop computers and mobile platforms like tablets and smartphones. OpenDocument Format (ODF) is used, making it compatible with OpenOffice.org, LibreOffice, and Microsoft Office. Calligra Suite contains the following applications: Calligra Words (word processor), Sheets (spreadsheets), Stage (presentations), Flow (diagrams and flowcharts), Kexi (visual database creator), Braindump (note taking), Plan (project management), Krita (drawing), and Karbon (vector graphics).