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

[detail level 1234]

Nfe
Nutf8	UTF-8 helpers for decoding byte streams, encoding char32_t values, and running ASCII-style character classification on char32_t
CChar32	Wrapper for char32_t with an operator<< that writes UTF-8
CArena	An arena pre-allocates so-called pages of size Arena::page_size_
CMemoryResource	A memory resource bridge in order to use this Arena for pmr containers
CAllocator	An allocator in order to use this Arena for containers
CDeleter
CRuntimeCast	Inherit from this class using CRTP, for some nice dynamic_cast-style wrappers
CDriver	Use/derive from this class for "global" variables that you need all over the place
Cis_bit_enum
CStreamFn	Wrap a callable f(std::ostream&) -> std::ostream& so it streams via operator<< and std::format
Cbasic_ostream_formatter	Make types that support ostream operators available for std::format
CTab	Keeps track of indentation level during output
CJoin	Join elements of `range` with `sep`
CLexer	The blueprint for a lexer with a buffer of `K` tokens to peek into the future (Lexer::ahead)
CPos	Position in a source file; pass around as value
CLoc	Location in a File
CParser	The blueprint for a recursive descent/ ascent parser using a `K` lookahead of Tokens
CTracker
CRing	A ring buffer with `N` elements
CRing< T, 1 >	Specialization if N == 1 - doesn't need a ring
CRing< T, 2 >	Specialization if N == 2; doesn't need a ring, we just copy
CSym	A Symbol just wraps a pointer to Sym::String, so pass Sym itself around as value
CString
CEqual
CHash
CHash
CEq
CSymPool	Hash set where all strings - wrapped in Symbol - live in