This directory is for quickfort blueprints. You can apply them to your fortress map with the DFHack quickfort plugin. See https://docs.dfhack.org/en/stable/docs/Scripts.html#quickfort for details. You can create blueprints by hand or by using any spreadsheet application, saving them as .xlsx or .csv files. You can also build your plan "for real" in Dwarf Fortress, and then export your map using the DFHack blueprint for later replay in a different fort. See https://docs.dfhack.org/en/stable/docs/Plugins.html#blueprint for more info. DFHack blueprints follow the original Quickfort 2.0 syntax. See https://github.com/joelpt/quickfort for joelpt's excellent documentation. There are many ready-to-use examples of blueprints in the library subfolder.