deltasql is a tool to synchronize databases with source code, which helps to keep database evolution under control. While developing mid-sized or big applications, developers make changes to the data model that go along with changes to the source code. From time to time, branches of source code are done to stabilize the code that will go to production. A sort of data model branch is also needed. deltasql provides a simple way to collect all scripts that change the data model and means to handle data model branches. The deltasql server runs on Apache and is backed by MySQL.
OpenGrok is a fast and usable source code search and cross reference engine. It helps you search, cross-reference, and navigate your source tree. It can understand various program file formats and version control histories like Mercurial, Bazaar, Git, ClearCase, Perforce, SCCS, RCS, CVS, or Subversion. In other words, it lets you grok (profoundly understand) the source.
SmartGit/Hg is a graphical user interface for Git and Mercurial which can work with SVN repositories. It supports cloning from common repository providers (e.g., GitHub, Assembla), assists Git newbies, and also offers the advanced, powerful Git features. It provides several tools to help create clean commits, for example by allowing the user to commit just parts of changes files and reordering and squashing unpushed commits. If you are using GitHub or GitHub Enterprise, SmartGit/Hg can work easily with pull requests (creation, resolving) and commit comments. SmartGit/Hg ships with a built-in SSH client, file comparer, and merge tool which are capable of syntax coloring for many languages.
ViewVC (formerly known as ViewCVS) is a Python/CGI-based system for viewing and interacting with Subversion and CVS repositories through your Web browser. It can browse directories, view changelogs, generate diffs, view arbitrary revisions, and display annotated ("blame") listings. It has full support for tags and branches, and contains a database-backed query system like Bonsai. It was initially based on the cvsweb work by Henner Zeller, but has been ported to Python and dramatically enhanced.
Quilt is a set of scripts to manage a series of patches by keeping track of the changes each patch makes. Patches can be applied, un-applied, refreshed, etc. The key philosophical concept is that your primary output is patches, not ".c" files or ".h" files, so patches are the first-class object here. It was originally based on Andrew Morton's patch scripts published on the Linux kernel mailing list a while ago, but has been heavily modified since then.
CVSps collect changesets from CVS repositories. It can be used either by humans to inspect changesets or as an exporter from CVS to other version control systems - it can be told to emit a fast-export stream to standard output. The code has been end-of-lifed and using cvs-fast-export instead is recommended.