Here is a list of all files with brief descriptions:

src
auth.c	Authentication function and handlers
common.h	Internally used functions and structures
compression.c	XEP-0138 Stream Compression
compression_dummy.c	Dummy Compression
conn.c	Connection management
crypto.c	Public interface for digests and encodings used in XEPs
ctx.c	Runtime contexts, library initialization and shutdown, and versioning
deprecated.c	File with deprecated API functions
event.c	Event loop and management
handler.c	Event handler management
hash.c	Hash tables
hash.h	Hash table API
jid.c	JID creation and parsing
md5.c	MD5 hash
md5.h	MD5 hash API
ostypes.h	Type definitions for platforms without stdint.h
parser.h	Internally used functions and structures
parser_expat.c	XML parser handlers
parser_libxml2.c	XML parser handlers
rand.c	Pseudo-random number generator
resolver.c	DNS resolver
resolver.h	DNS resolver
sasl.c	SASL authentication
sasl.h	SASL authentication helpers
scram.c	SCRAM-SHA1 helper functions
scram.h	SCRAM helper functions
sha.h	SHA-1 hash API
sha1.c	SHA-1 hash
sha1.h	SHA-1 hash API
sha256.c
sha256.h	SHA-256 hash API
sha512.c
sha512.h	SHA-512 hash API
snprintf.c	A snprintf implementation
snprintf.h	Compatibility wrappers for OSes lacking snprintf(3) and/or vsnprintf(3)
sock.c	Socket abstraction
sock.h	Socket abstraction API
stanza.c	Stanza creation and manipulation
tls.c	Generic TLS functionality
tls.h	TLS abstraction API
tls_dummy.c	TLS dummy implementation
tls_gnutls.c	TLS implementation with GNUTLS
tls_openssl.c	TLS implementation with OpenSSL
tls_schannel.c	TLS implementation with Win32 SChannel
util.c	Utility functions
util.h	Internally used utility functions
uuid.c	Generation of UUID version 4 according to RFC4122
strophe.h	Strophe public C API definitions