Here is a list of all files with brief descriptions:

[detail level 1234]

include
mrtklib
mrtk_antenna.h	MRTKLIB Antenna Module — Antenna phase center model and parameter I/O
mrtk_astro.h	MRTKLIB Astronomy Module — Sun and moon position computation
mrtk_atmos.h	MRTKLIB Atmosphere Module — Ionospheric and tropospheric models
mrtk_bias_sinex.h	MRTKLIB Bias SINEX Module — BIAS-SINEX data types and I/O functions
mrtk_bits.h	MRTKLIB Bits Module — Binary bit operations and CRC functions
mrtk_clas.h	CLAS (QZSS L6D) CSSR decoder and grid correction type definitions
mrtk_cli.h
mrtk_const.h	MRTKLIB Constants — Physical, navigation, and system constants
mrtk_context.h	MRTKLIB Context — runtime context for processing, trace, and error handling
mrtk_coords.h	MRTKLIB Coordinates Module — Coordinate transformations and geometry
mrtk_eph.h	MRTKLIB Broadcast Ephemeris Module — Satellite orbit/clock types and Kepler/GLONASS/SBAS orbit computation functions
mrtk_fcb.h	MRTKLIB FCB Module — Fractional Cycle Bias data types and functions
mrtk_foundation.h	MRTKLIB Foundation — Common types, standard includes, and system constants (MAXSAT, NFREQ, MAXOBS, observation codes, etc.)
mrtk_geoid.h	MRTKLIB Geoid Module — Geoid height models
mrtk_has.h	MRTKLIB Galileo HAS Module — E6-B C/NAV HAS page collection and Message Type 1 (MT1) decode into ssr_t corrections
mrtk_ionex.h	MRTKLIB IONEX Module — IONEX ionospheric TEC map I/O and interpolation
mrtk_l6.h	MRTKLIB L6 Module — QZSS L6 frame header parsing
mrtk_lambda.h	MRTKLIB Integer Ambiguity Resolution Module — LAMBDA method
mrtk_madoca.h	MRTKLIB MADOCA-PPP Module — QZSS L6E CSSR message decode functions
mrtk_madoca_local_comb.h	MRTKLIB MADOCA Local Combination Module — local correction data combination functions
mrtk_madoca_local_corr.h	MRTKLIB MADOCA Local Correction Module — local correction common functions and constants
mrtk_mat.h	MRTKLIB Matrix Module — Matrix/vector operations and estimation
mrtk_nav.h	MRTKLIB Navigation Module — Navigation data types and satellite/nav utility functions
mrtk_obs.h	MRTKLIB Observation Module — Observation data types and utility functions
mrtk_opt.h	MRTKLIB Options Module — Processing and solution option types
mrtk_options.h	MRTKLIB Options Module — Configuration option parsing and system option management
mrtk_peph.h	MRTKLIB Precise Ephemeris Module — Earth rotation parameter types and ERP I/O functions
mrtk_postpos.h	MRTKLIB Post-Processing Positioning Module — Post-processing positioning orchestrator
mrtk_ppp.h	MRTKLIB Precise Point Positioning (PPP) Module
mrtk_ppp_ar.h	MRTKLIB PPP Ambiguity Resolution Module
mrtk_ppp_rtk.h	PPP-RTK positioning engine declarations
mrtk_rcvraw.h	MRTKLIB Receiver Raw Data Module — Receiver raw data types and decoder functions for various GNSS receiver protocols
mrtk_rinex.h	MRTKLIB RINEX Module — RINEX file read/write types and functions
mrtk_rtcm.h	MRTKLIB RTCM Module — RTCM message types and functions
mrtk_rtkpos.h	MRTKLIB RTK Positioning Module — relative and precise positioning
mrtk_rtksvr.h	MRTKLIB RTK Server Module — real-time positioning server
mrtk_sbas.h	MRTKLIB SBAS Module — SBAS message decoding and corrections
mrtk_sol.h	MRTKLIB Solution Module — Solution data types and I/O functions
mrtk_spp.h	MRTKLIB Single-Point Positioning Module — SPP functions
mrtk_station.h	MRTKLIB Station Module — Site environment parameter I/O
mrtk_stream.h	MRTKLIB Stream Module — stream I/O abstraction layer
mrtk_sys.h	MRTKLIB System Module — OS/filesystem utility functions
mrtk_tides.h	MRTKLIB Tides Module — Tidal displacement corrections
mrtk_time.h	MRTKLIB Time Module — GNSS time types and conversion functions
mrtk_toml.h
mrtk_trace.h	MRTKLIB Trace Module — debug trace and logging functions
mrtk_version.h.in
mrtk_vrs.h	MRTKLIB VRS-RTK Module — double-differenced RTK using CLAS VRS
mrtklib.h	MRTKLIB Public API — Context Management and Logging
rtklib.h
rtklib.h
src
clas
mrtk_clas.c	QZSS CLAS (L6D) CSSR decoder and bank management
mrtk_clas_grid.c	CLAS grid interpolation for troposphere and STEC
mrtk_clas_isb.c	ISB (inter-system bias) and L2C phase shift corrections
mrtk_clas_osr.c	CLAS SSR-to-OSR (Observation Space Representation) conversion
core
tomlc99
toml.c
toml.h
mrtk_bits.c	MRTKLIB Bits Module — Implementation
mrtk_cli.c
mrtk_context.c
mrtk_coords.c	MRTKLIB Coordinates Module — Coordinate transformations and geometry
mrtk_core.c	Core implementation of MRTKLIB context management and logging
mrtk_mat.c	MRTKLIB Matrix Module — Matrix/vector operations and estimation
mrtk_sys.c	MRTKLIB System Module — Implementation
mrtk_time.c	MRTKLIB Time Module — Implementation
mrtk_toml.c
mrtk_trace.c
data
rcv
mrtk_rcv_binex.c
mrtk_rcv_crescent.c
mrtk_rcv_javad.c
mrtk_rcv_novatel.c
mrtk_rcv_nvs.c
mrtk_rcv_rt17.c
mrtk_rcv_septentrio.c
mrtk_rcv_skytraq.c
mrtk_rcv_ss2.c
mrtk_rcv_ublox.c
mrtk_bias_sinex.c
mrtk_convrnx.c	RINEX translator for RTCM and receiver raw data log
mrtk_eph.c	MRTKLIB Broadcast Ephemeris Module — Kepler/GLONASS/SBAS orbit and clock computation functions
mrtk_fcb.c
mrtk_ionex.c
mrtk_l6.c
mrtk_nav.c	MRTKLIB Navigation Module — Implementation
mrtk_obs.c	MRTKLIB Observation Module — Implementation
mrtk_peph.c	MRTKLIB Precise Ephemeris Module — Earth rotation parameter I/O, precise ephemeris/clock computation, and satellite antenna offset functions
mrtk_rcvraw.c
mrtk_rinex.c	MRTKLIB RINEX Module — RINEX file read/write functions
mrtk_sbas.c	MRTKLIB SBAS Module — SBAS message decoding and corrections
has
mrtk_has.c
mrtk_has_rs.c
mrtk_has_rs.h
madoca
mrtk_madoca.c
mrtk_madoca_iono.c
mrtk_madoca_local_comb.c
mrtk_madoca_local_corr.c
models
mrtk_antenna.c	MRTKLIB Antenna Module — Implementation
mrtk_astro.c	MRTKLIB Astronomy Module — Implementation
mrtk_atmos.c	MRTKLIB Atmosphere Module — Ionospheric and tropospheric models
mrtk_geoid.c	MRTKLIB Geoid Module — Geoid height models
mrtk_station.c	MRTKLIB Station Module — Implementation
mrtk_tides.c	MRTKLIB Tides Module — Tidal displacement corrections
pos
mrtk_lambda.c
mrtk_opt.c	MRTKLIB Options Module — Default processing and solution options
mrtk_options.c
mrtk_postpos.c
mrtk_ppp.c
mrtk_ppp_ar.c
mrtk_ppp_iono.c
mrtk_ppp_rtk.c	PPP-RTK positioning engine
mrtk_rtkpos.c
mrtk_sol.c
mrtk_spp.c
mrtk_vrs.c	VRS-RTK positioning engine
rtcm
mrtk_rtcm.c
mrtk_rtcm2.c	MRTKLIB RTCM Module — RTCM ver.2 message decoder
mrtk_rtcm3.c
mrtk_rtcm3_local_corr.c	MRTKLIB RTCM Module — RTCM3 local correction message functions
mrtk_rtcm3e.c
stream
mrtk_rtksvr.c
mrtk_stream.c
mrtk_streamsvr.c	Stream server functions for data relay and format conversion
ntrip_chunk.h