The Glyphmakers' Graves are the remnants of an alien civilization found in a particular region of deep space. As far as anyone can tell, they mostly left behind thousands of small outpost stations of an unknown purpose. Their written language appears to be primarily based on shape and color, hence the name Glyphmakers.
While their stations have valuable materials and technology that can be salvaged, they are also still protected by robotic defenses, and Accord guidelines recommend that each station be boarded by a pair of battlesuit-equipped explorers. The Gemini Assault Class scout is perfectly suited to this mission profile.
The Glyphmakers were particularly skilled at circuit miniaturization, a technology that humankind has been slow to develop. Construction guidelines found at their stations use the universal language of simple mechanical engineering, and are relatively easily interpreted by any technologically-inclined human in order to adapt Glyphmaker salvage into new useful applications. In other words, Glyphmaker stations contain blueprints and insights for new items and the materials with which to build them.
Theme note: Items made with Glyphmaker blueprints should not be thought of as strictly alien technology -- rather, you are reinterpreting their instructive documents for your own purposes. For example, Glyphmakers did not develop service robots that look human and speak a human language, but materials they left behind will help you to build these yourself. Similarly, Glyphmakers may or may not have had rift drive technology, but alien guidelines and devices for manipulating electromagnetic fields will help you develop rift sail extenders.
A rift drive is required to reach the Glyphmakers' Graves, meaning that exploring their stations is decidedly NOT an activity for newer characters. You will be served best by waiting until you qualify for a rift drive yourself, at 300 exploration points or 3000 industry points, before you begin exploring these stations.
The location of the Glyphmakers' Graves is not a secret, but the information is beyond the scope of this help file. Please discover it by interacting with other characters. Since the activity requires a partner, someone will likely be quite eager to teach you how it is done!