We don't use a SVN based repo, we use a Mercurial powered one, so you can't sync using SVN tools. Google code has resources you can hit up for accessing Mercurial repos with whatever OS and/or editor you use.

The other blam-based games I've written code for is very specific. The only other engine extensions I've written are for Halo 2 Xbox and H2V's tools (so there are no source projects for a Stubbs game for any platform). Neither have been synced yet as the current goal is just to get Halo 1 up and in running order. The H2X codebase also makes use of a generic Xbox1 "module" (aka, "trainer") system which I'm still finalizing the standards for since I'm wanting modules to be loadable by future Xbox (ie, dxbx or cxbx) emulators without having authors reprogram/relink their shit. BlamLib (which is 95% C#) has been positioned for future syncing to the repo but I'm still redacting some parts of the code not meant for public use and also adding some test code to help illustrate its usage.

Shared files are typically just there for generic code sharing or for project sharing. IE, the Halo1_CE and Halo1_CheApe both use shared project source files. This is so I don't have to fuddle around with setting up some honky tonk LIB which only complicates the build process that much more. Shared files are just that, shared to keep out dup'd code and to allow easier compiling/linking of relate-able code.