This template should be used on pages in the বিষয়শ্রেণী: namespace, and automatically generates descriptions and categorization for categories of a recognized type (see below). It is implemented by Module:category tree and its submodule Module:category tree/poscatboiler. It is preferable not to invoke this template directly, but to simply use {{auto cat}} (with no parameters), which will automatically invoke this template on appropriately-named category pages.