Of course! Silly me. It says so right on the package description. Thanks @v3xx! I have removed zeitgeist a long time ago, so even if it did something, the Activity Log Manager wouldn't work without it. On a unrelated note the package is missing a Recommends to zeitgeist. I'll fill in a bug report.
I'm not very happy with how the Recent documents currently works. It's too limited. I require the ability to define the maximum number of entries and blacklist files or directories, preferably with support for regex expressions. I think I'll forget about MATE implementations and I'll instead do something on bash with either YAD or dzen.
I want to learn about both Caja and the MATE panel interface and applet programming. I wanted to create a new weather applet, for instance. But I just can't seem to find enough motivation currently to study it. So a script with YAD or dzen will suffice for now.