Here are the classes, structs, unions and interfaces with brief descriptions:

Ndxx
Nassert	Main namespace for dxx::assert module
Cfailure	A default error type that is thrown when the assertion fails
Nerrors
CErrno	Tag type, helps indicate that errno info should be added to the error message
CError	Exception class that supports construction from std::format-like args and automatic errno capture in the message
Nhttp
CHeaderCompare	HTTP headers comparison struct - they must be case-insensitive
CPathNode
CPendingConnection	An awaitable object that allows the handler code to respond to the request at a later point in time
CRequest	HTTP request structure. Also used for multipart request data
CRequestError
CResponse	Server's response to the client
CServer	A simple HTTP server
CServerError
CSimpleTask	A single connection handler coroutine task
Cpromise_type
CStreamError
Nmath	The main namespace of the dxx::math module
Ncontainer_traits	Advanced type traits for containers
Nsize	Different types of sizes the vector container types can have from the libraries' perspective
CDynamic	Size is a runtime value during construction and can be changed
CRuntimeFixed	Size can't be changed but unknown at compile time
CBound	Size is a runtime value during construction and can be changed, but limited by a compile-time constant
CStatic	Size is a compile-time constant and cannot be modified
CTraits	Additional traits that tell the library how to handle the vector container type (when std::ranges facilities aren't enought)
Ndetail
CRealOf
CRealOf< T >
CNorm	Defines a norm. Only norm field is required, all other fields can be assigned a nullptr
CSub	Default difference is subtraction
Noverload	Main namespace for dxx::overload module
Cfn_ptr_wrapper	Class == int means free function (can't have a method on int)
Cwrap_callable
Cwrap_callable< Ret(Class::*)(Args...)>
Cwrap_callable< Ret(Class::*)(Args...) const >
Cwrap_callable< Ret(Class::*)(Args...) && >
Cwrap_callable< Ret(*)(Args...)>
COverload	Overload pattern implementation. Itself does not differ from https://www.cppstories.com/2019/02/2lines3featuresoverload.html/, extra functionality comes from CTAD. See module description for usage
Nselftest	Main namespace of dxx::selftest module
CLifetimeTester	A simple class for tracking object moves/copies during their lives in containers
Ctest_failure	The exception type used by test assertions
CUnitTest	Create an object of that class to declare a unit test
Nutils	The main namespace of the dxx::utils module
Nheap	The namespace for heap-allocated replacements for some standard library classes
COption	An std::optional replacement with heap-allocated storage
CAs
CDefer	Class for deferring operations until the end of lifetime
CFileDescriptor	RAII file descriptor. Wraps an integer file descriptor and defers closing it to the desctructor
CFOf
CFOf< 32 >
CFOf< 64 >
CIOf
CIOf< 16 >
CIOf< 32 >
CIOf< 64 >
CIOf< 8 >
CUOf
CUOf< 16 >
CUOf< 32 >
CUOf< 64 >
CUOf< 8 >